Sets over Sets, Oh My!

My session yesterday started off very badly. The very first hand someone posted in MP, and I also posted $1 in the CO, and picked up 22 (sweet pocket ducks for the KillerDucky, quack quack!). UTG limps, MP poster checks, I check, Button raises to $4. SB and I both call, 3 way to the flop. It's 842 rainbow, awesome flop for me! SB checks and I check, and Button bet $4 into a $15.50 pot. So really the button could have almost any two trying to steal the limper + 2 posters + blinds. And now he's betting very weak on the flop? SB folded so I decided to get cute and min raise to $8. I figure this keeps overcards and any pocket pair in. Sure enough he just calls. Turn is a 5, now two hearts. There are quite a few straight draws now (any ace has a gutshot) so I decide to put in a real bet. For some reason I choose just 1/2 the pot which on the smallish side. But then suddenly Button pushes allin, and its $73 to call and the pot is $134.50. I have a set, so I think it's a must call situation, since there's almost no way he has 67 for a straight, I just have to pray it's an overplayed AA/KK or something. Unfortunately he had 55, spiking a higher set on the turn, and I lose my entire stack the very first hand! Revenge of the Straight Flush (draw) The rest of the night was going ok and I was coming back from the huge loss first hand. But my previous good fortune with straight flushes was about to change. It's folded to me in the CO with 75s, I raise to $4, only the BB calls. Flop comes J86, with the 86 in my suit, giving me a real monster drawing hand. The pot is already $8.50 and BB is a little short only having $39 left, so I really feel the only way to play this is fast. He checks and I bet out $6, he min-raises to $12, I push, he calls. Well he had KK and he dodges 15 cards twice to win a $83.50 "coin flip" (actually I had 56% equity on the flop).