This has been bugging me all night and i am thinking was this the corect play in the given circumstances...................
So, i`m playing in a live 20 quid freezeout 70+ players start. I have been picking up a few pots here and there, not getting into any races and confidence was high. Were down to the last two tables, 7 on each. Blinds 1000/2000. Im on the button with 12K in chips and pick up..

Everyone folds to me and I flat call. SB calls, BB checks. Flop

SB around 20ish K in chips, Checks, The guy had ben playing fairly tight but if he made a move it was generally all in pre flop. BB, who had been raising up quite a lot, 16K in chips, plus he nearly got knocked out on a previous table right at the start of the tournie with

but hit a straight flush calling an all in against AA pre flop, takes a deep breath and says "im all in". Now, because of his previous plays i put him on a flush draw or maybe 10x, anyway i call. The SB then starts huffing and puffing, count his chips at least three times and (seemingly) reluctantly calls.
SB has

BB has

Turn

River

Now, obviously this cost me the tournie but like I said its been bugging me, The put of 36K, even though a bit under odds for my draw and I held a diamond, looked good enough for me. i was wondering given the above circumstances what would people have done?
Thanks in advance.