I've been told by doctors that a blood test at 1 month is about 90% accurate, although you'll have to come back at 3 months and 6 months just to be 100% sure. And HIV usually comes from repeated exposure. And then there are anti-virals you can take if it just happened. But I think certainly if you think you have been raped, you should probably get some counceling.
Paranoia is an interesting subject. This was one of the worst parts of drinking for me. It was so subtle, because you can never be sure when you're involved in it.
I was a binge drinker, not an everyday drinker. After a while, it became unmanagable, but although I didn't feel a strong chemical dependency, it took me about 10 tries to get some real time. Gosh. I so don't miss those staggering drunk nights when I had to dangle my foot off the bed to keep the room from spinning. All those bars desperately seeking contact and finding only my own apparent inadequacy in the eyes of the young.