What do you think

I'm a first time poster but have been reading the posts of others for a long time and and enjoy all of them. Anyway, I was playing in 50euro re-buy tournament in my local casino on Friday night when the follwoing hand came up. There are 25 left out of 110 entries. Only the final table gets paid.I'm slightly below average on 25,000 chips in the small blind(blinds 800/1500) Everybody folds around to me and I call with A7off. The big blind checks. The flop comes down Q [img]/images/graemlins/heart.gif[/img]7 [img]/images/graemlins/heart.gif[/img]3 [img]/images/graemlins/club.gif[/img]. I bet 3000 and the big blind immediately moves all-in. He has me covered. I know this player and I'm certain he hasn't hit top pair or two pair as I think he would have tried to extract more value from the pot with a call seen as I'm relatively weak only calling pre-flop. I put him on the flush draw and after a while I call. He turns over J [img]/images/graemlins/heart.gif[/img]9 [img]/images/graemlins/heart.gif[/img]. Now it's worse than I thought as he also has two overcards to my pair of sevens as well as the flush draw. When making the call I thought low flush draw as he seemed weak pre-flop. He hits a J on the turn and I'm out. Was it a bad call? should I have waited for a better spot. If I win the hand I'm well in contention. Any comments appreciated.