What would you have done?

[largos]

I am in a 100 dollar tourney middle stages . My stack is about 7000 , average about 5500. There is about 28 players
left . We have all been playing just a few hands together
so we don`t know eachother. I am in cut-off and everyone folds to me, blinds 200-400. I get AK suited and go all-in.
Everyone folds to the big blind who after some hesitation calls (He has 6500 in chips) . He shows AT suited. He hits a T and wins.GRRR
How would you have played it?