Seriously, your penis is working. But between the prozac (may be dulling sensation somewhat?) and your twice a day on your own, you aren't leaving enough time for desire to build up again? I know boys are different from girls, but yeah I would bet the meds are messing with your refractory period. At least in terms of you being in touch with your feelings. When I first started on prozac, I was announcing it to everybody, and a bagger told me (he would have been closer to your age) that he quit it when his gramma died cuz he didn't feel anything. I told him I didn't think I would have that problem cuz both my grammas*were already dead. So while it takes away bad feelings, it also takes away good feelings, and you're just kind of left with medium, more standard or reliable feelings? I would advise trying to find out what works, making adjustments to get what you really want back. Don't wack until after you've been with your gf, for example.