Bad Laydown?

[kingstalker]

Pokerstars 5+50 rebuy
blinds 100/200
I have 11,000 in chip
I am dealt [img]/images/graemlins/diamond.gif[/img]7 [img]/images/graemlins/heart.gif[/img]6 in the SB
MP calls 200
LP calls 200
I complete the SB
BB checks
the flop comes down:
[img]/images/graemlins/spade.gif[/img]4 [img]/images/graemlins/club.gif[/img]7 [img]/images/graemlins/spade.gif[/img]5
I bet 800, trying to pick the pot up,BB folds,MP and LP call.
Turn [img]/images/graemlins/spade.gif[/img]8
Damn, gives me a straight but also completes the flush draw and gives anybody with a 6 a straight as well.
I check, probably should of bet 1000 here just to not give any free cards if they werent on the flush draw
MP checks and LP checks.
river is the [img]/images/graemlins/club.gif[/img]9
this weakens my hand a little bit as well as now the gutshots have hit their hand as well, I check planning to call a moderate bet and now MP goes all in for 16,000 into the 3200 pot,LP folds, I think at first that is a very strange all in because why would he go all in with the flush when both his opponets had shown weaknesses on the turn on and the river and werent likely to call it? Finally I folded because I could of been right and MP not have the flush but still we split the pot if both of us have a 6.Anybody think I should call here?