Well, the biggest threat to your health is your alcoholism. Being an alcoholic that binge drinks takes a toll on all things related to your health including your judgement and anxiety. Personally, for a one time exposure, I wouldn't have gone on pep. There is less than 1 percent chance of transmission from an unprotected sex encounter. Like, almost nothing. They normally reserve pep for situations in which the other person is KNOWN to be hiv positive. Pep is hard to take. Pep works and looking for 'percentages' tells me that your anxiety is ruling your day. They advise NOT to drink when taking pep. Not because it will make your medication less effective but because pep drugs are metabolized in the liver as is alcohol and your liver health is at stake. Alcohol will not impact if pep can work but you are just taking more and more risks with your own health for the sake of drinking. So, go dry for now. Seek help if you can't.