Sex without love?

[DeadKennedys]

I've hooked up a bit during my life. And granted, it was fun for a while. I'm not saying I'm some mega stud, but at highschool/college age, you go to a party with beer and chances are you're getting laid. You don't have to do anything or have an ounce of charisma to get sex in high school.

There was a girl, the only one I ever loved, and we broke up, but we have had sex off and on in the past half year. Unlike while we were dating, afterwards I always have this sinking feeling in the pit of my stomach and I get depressed. Even when I fly solo, I get extremely depressed after climax. And no, I'm not catholic.

Is there something wrong with me?