If you're circumcised try using lube to increase sensitivity.
First out there are a lot of women and girls who will just having you for sex, 20 minutes of sex, here we go.
Just try cutting back on your meds to see which work best, or see if you can find a herbal remedy try having a look on earthclinic under your symptems, but cut out the fast masterbating, it will never do you any good, remember what you do with your hand stays in your brain.
Good luck
Prozac is known for having that effect. If you can do without the meds, possibly by substituting a different med or maybe exercise, then you might give it a try. But if you decide to try this, talk to your doctor and do be sure to substitute something else. Don't just go off your meds cold turkey.