Key Hand From $3r

I feel like recently I've consistently been making the wrong decision in key hands like this one (or hopefully making the right decisions and getting unlucky!), so I'd like to solicit some outside opinions.

Reads:

I've been aggressive pre-flop, haven't had to play a lot of flops. A few players had taken note of my aggression and started playing back at me, so I've slowed down recently, don't know if that's been noticed or not.

The only other time I saw UTG+1 limp in early position, he had 66. He likes to slow-play big hands, though, and I've seen him do it with trips out of the blinds.

MP1 limped fairly frequent a few levels ago, but hasn't been doing it as much now. The two times I saw her cards when she had limped, she had JTo and AA (and the AA was after someone else had already limped).

PokerStars No-Limit Hold'em Tourney, Big Blind is t1200 (8 handed) internettexasholdem.com

SB (t29545)
Hero (t35430)
UTG (t56715)
UTG+1 (t38890)
MP1 (t30033)
MP2 (t17235)
CO (t22510)
Button (t31615)

Preflop: Hero is BB with 8[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/heart.gif[/img].
1 fold, UTG+1 calls t1200, MP1 calls t1200, 3 folds, SB completes, Hero checks.

Flop: (t4725) T[img]/images/graemlins/club.gif[/img], 8[img]/images/graemlins/heart.gif[/img], 7[img]/images/graemlins/heart.gif[/img] (4 players)
SB checks, Hero bets t3500, UTG+1 calls t3500, MP1 calls t3500, SB folds.

Turn: (t15225) 8[img]/images/graemlins/diamond.gif[/img](3 players)
Hero bets t10000, UTG+1 calls t10000, MP1 raises to t25258, Hero ????