I don't think you did anything wrong. These men were just trying to use guilt to get what they wanted from you. You should not blame yourself because you didn't want to give in to thier demands. Thier behavior towards you doesn't warrant them getting anything. No one wants to be used and that is exactly what they were trying to do to you.

It sounds like you may be susceptible to depression. One of the criteria for major depressive disorder is inappropriate guilt and feelings of worthlessnss. Also reduced pleasure from activitiess you once enjoyed, reoccurent thoughts of suicide or death, fatigue or loss of energy, difficulty concentrating.

Most colleges have counseling services. Maybe speaking with them could give you some relief. If you want someone to talk to feel free to p.m. me. I hope things improve for you.