Fold preflop!

Playing these small/mid pairs in EP is going to kill your bankroll for exactly the reasons that this HH illustrates.

On the flop:

With that much action in front of you and 4 left behind you, I would seriously consider folding middle set. There is a straight on the board and the only card that you really want to see on the turn and river is the case 8. Anyone behind you with 9-10 and 2 spades could suddenly escalate this thing into an all-in coup. Do you want to be calling off your whole stack here with just a naked middle set?

On the turn:

OK, by some miracle, you now have the button. The turn also fills you up. SB makes a half pot bet and BB calls! You are screwed. Unless both SB and BB are complete maniacs, you are drawing to 1 out. One of them had to have J-J or 7-7, both of which are beating you. It is again time to fold. If you think both a complete loons, you should be raising here. Calling is the worst of the 3 options IMO.

On the river:

You found the fold button that had been hiding from you since before the flop. Whew!