Lake drama and drowning girl

If you want drama and excitement, go to a lake. 2 weeks ago I sprained my left ankle on my first wakeboarding session. Driving home that afternoon I had a car accident happen right next to me at 50mph where some loser tried to overtake me in a dodgy van approaching a crest, when an oncoming car came over the crest. The oncoming car swerved to avoid a head-on, while the guy in the van panicked and somehow managed to lock his brakes and turn broadside, skidding away from me across the oncoming lane and off the road, taking out someone's letterbox. The approaching driver swerved even wider a full 8-10m off the road right next to the fence, but the right front of the van hit the left rear of the car, sending both into a spin. Once they'd stopped, the van driver immediately threw it into first and floored it, and drove away skidding in a mad rush. I shoulda chased him and got his plates, stupid of me, I think I was a little shocked, something told me not to leave the scene but I could have come back. The oncoming car was bashed up on the rear corner a bit, the 50-something guy driving it was cool as, but his wife was hysterical. I hung around, gave the police my story, then went home.
Tuesday arvo, we helped out a boat full of 6 guys and a girl who had a flat battery, and Todd's starter kit solved that problem. I was trying more jumps and sprained the same ankle again with the same crash, this time badly, had to put it on ice from the esky ('ice chest'). At least Nate photographed it in burst mode! But the most significant event of all, was when we were headed back to the ramp after our epic session in perfect glass conditions, we found as we approached, a girl in the water clinging to the end of the little jetty next to the ramp! It only took seconds after wondering if she'd been swimming, to realising she was in trouble as she tried to pull herself up onto the jetty but couldn't. Todd quickly pulled the boat alongside the jetty, I jumped off and got to the end of the jetty and said 'hey are you alright?'
She didn't even look up, so I put my hand on hers and said 'it's ok, i'm here, take my hand.' She then seemed to realise someone was there, looked up at me and she was utterly exhausted, but took both hands and I pulled her up out of the water and onto the concrete pier. Her towel and car keys were behind me, but her thongs were floating away nearby, about 8m away. She was a young girl, clothed in bathers, a shirt and short shorts. After catching her breath for half a minute, I asked what happened, and that's when it all turned bizarre.
She didn't answer half of my questions, I asked how she got in the water, she'd only say 'I was upset'. She said it was scary, and that she went all the way to the bottom, but couldn't remember how she got back up. I jumped off and swam over to her thongs and got back and pulled myself back up, the jetty is about a metre above the water. Todd was still in the boat nearby, I said it's cool I'll sit with her a while until she calms down, so he went and put the boat on the trailer. I sat with her a long time, even after the boys had loaded the boat and I told them to go coz I drove myself and she wasn't ready to drive yet. She was 24 and worked as a waitress in the city, and was at the lake alone. We talked for a while, but she avoided talking about anything to do with what had happened. She even suggested jumping in the water for a swim, which I found crazy since she had just almost drowned, but she wanted to so we did, she can swim but only just. After I pulled her back out again, and asked if she was ok to drive, she said no she wanted to stay. I didn't want to leave her alone, and had nothing to do, so we stayed until after dark, and then finally when a storm was approaching, I said I had to go. I had offered her a couple of times to follow me back to Todd's and I'd fix her some dinner and she could have a shower & a dry change of clothes, but she refused every time, until I had started to walk away and she suddenly asked to come with me. But, in my car.
Her awkward conversation had started to irritate me a bit but for some reason I agreed, meaning I'd have to drive her back out to the lake later to drop her off at her car, 15min each way.
When we got home, she followed me around, I didn't want her in my bedroom, but I turned around as she sat on my bed in her damp clothes ready to lie down! I said 'no no, up you get, have a shower first and we'll get you dry clothes'. Todd was home and got a shirt, I gave her some trackies, she got changed in the bathroom and I started dinner, and then she went straight into my room and passed out on my bed!
I couldn't believe it, it was worrying, so Todd and I discussed it all, and then during dinner we heard her calling out in anguish, like she was having bad dreams. I said there's something seriously wrong with this girl. She had shown me scratches (probably from the jetty) but also she had bruises (probably not from the jetty). We let her sleep, and Todd offered to drive her back to the lake in the morning as it was on his way to work. I wrote her a note explaining where she was and what had happened, put it on her stuff next to the bed, stole back one of my pillows and slept on the couch. She called out several times during the night in the same way, I left the door to my room open. I woke up at 3:30am to find her walking around in the loungeroom in the dark! I beckoned her over to the couch, she couldn't remember where she was, she missed the note in the dark, but she remembered me. It was only then that I smelt the alcohol on her breath, and wondered why I didn't notice it earlier. She's either a very good drunk, or her drowning experience had sobered her up a lot. I sent her back to bed, and sometime after 6am Todd was up. We had been discussing possibilities over dinner, and I had put my money on her being abused and attempting to commit suicide. But after learning she was drunk, we agreed that she had probably been abused, and was drinking away her sorrows by the lake, and fell in. Todd drove her back to the lake, and asked her if she had been abused. She didn't answer, and Todd told her that nobody should have to live in fear, and if she was being abused she should tell someone about it, and he offered his number to her if she ever wanted to call and talk about anything. She just said 'ok' and took his number, which to me indirectly proves that we were right.
And that's the end of the story. I hope she ends up ok. She's the fourth person I've 'rescued' from distress in water in my life, and sadly not the first girl I've met who has been abused, or suicidally depressed.