When poker is beautiful - Flopping a boat

Results have been ok last few weeks, a few cashes here and there and I've been pretty happy with my game.
I played a  tournament last week where I got involved in a big pot with four other players.
To summarise the essentials:

Preflop raise to 4X from UTG

Me -  Seat 5 Pocket 3,s  I call

Seat 6 calls

Seat 8 calls.

Flop comes a sweet 6, 6, 3 with 2 hearts.

UTG checks,
 I check
 Seat 6 bets 800,
 Seat 8 calls,
 utg calls
 and I flat it.

Theres now about 7k in the pot.

Turn comes a jack of hearts. This is getting better and better. The flush just got there, but sadly its check, check, check, check.

Cooler

River comes Ace of spades.

This is about as good as it gets.
 The full house isn,t exactly the nuts, but with potential flushes and ace somethings getting there, its probably the perfect river for me and...

UTG bets 1200
I raise  to 2600, seat 6 folds, and seat 8 reraises to 7500.

After much deliberation, the initial raiser (UTG) folds.

 I reraise all in for about 15k.
Seat 8 snaps me off and tables pocket jacks.

Bollocks.