I'm 18 and pretty much stopped caring about sex almost instantly. I've been having sex since I was 15, but now I'm just done with it. About a week ago, I no longer had erections for no reason, and over of 3-4 days I had no enthusiasm about sex. I could look at pornography and I don't understand it anymore and looked at it with disdain. My girlfriend was fooling around with me and I just kinda got up and was like "not now". I'm healthy and everything, no medical problems. Whats the deal with me? I can still get erections if I force it, but I look at sex with a "whatever" attitude.