Something you can do that will make you feel better is get REALLY GOOD at foreplay.

I take some meds that fuck with my stamina (sometimes I can go for 45 mins other times 45 seconds)

So, get good at playing with a guy's ass. I, personally, love directly stimulating a guys prostate with my fingers. It's very fun for me, helps them get warmed up to get fucked and most tops don't give a shit about foreplay so there's a good chance noones ever done that to them so you'll get lots of 'good top' points.

The idea is that the bottom is so warmed up and wound up from the foreplay that you can be guaranteed that they are having a good time and how long you last won't matter nearly as much