If you feel you are becoming severely intoxicated after only one or two drinks, get help. You may have ingested GHB or Rohypnol. Never leave a bar or club with someone you have just met, especially if you are feeling intoxicated. Beware of someone who wants you to go outside for a breath of fresh air. Unfortunately, someone who seems to be a nice normal person can turn out to be a rapist.
Rapists come from all social and professional backgrounds.
However, there are some men who are more likely to be sexually aggressive than others. Such men generally have little respect for women. Men who ignore your personal space boundaries. Don't feel guilty and don't just try to forget about it. You didn't ask to be raped.