OK fitness crew, I've got a stamina problem h:

I generally do circuits, and my first time around I can usually beast out some good numbers, second time is generally like 75% of first set (either in terms of reps, weight or both), third set is pretty weak, and so on. For example, tonight I hit the gym and did dumbbell press. I beasted out 85x14 the first set and felt like super man... second set I struggled to finish 70x12. :hs: I would just start lower, but then I don't feel like I'm getting the same workout... plus there's the cool factor of using the really big weights Any suggestions?