Jesus! I can't believe they spiked you with Rohypnol. That aint on. I'd be fuming about that. I've had mates spike me in the past, but with stuff they knew I'd had before, which is bad enough, but as mates we had an idea of what our limitations were. Even still that got me really pissed off. If they'd ever have used Rohypnol I'd have disowned them.
Maybe I'd feel a bit more at ease with your situation if I knew why your mates even had the stuff on them in the first place. Not saying they are rapists, but all they do is render people unconscious and delete their memories, which aren't exactly positive experiences for drugs. And that could have ruined more than just a day out. Anything could have happened.