Bad Play

My results yesterday and today are below average.  Overall, I am down about $5.00 for the last couple days.
Last night, I played in a couple of large field $2 tournaments.  I failed to cash in either one. 

Today, I was in good position to make a final table, but made a bad play that killed my momentum and my chance to make the money. 
I had picked up a few big hands and had about 7500 in chips.  I was the chip leader.  Blinds were 60/120.  I had AQ 2 off the BB.  I raised to 300.  The player to my immediate left moved in for 2700.  I had played with this player before and had seen him make similar plays.  I put him on an AJ or AT or an under pair.  For some idiotic reason, I decide I dont mind playing a coin flip.  He had 77 and I failed to improve.  He doubled up and I went from chip leader to 5th in chips.  After this hand, I was tilting.  I made the final table with a small stack.  On my final hand, I had A6 and pused allin for 900.  The blinds were 120/240.  The BB called with KQ and spiked a K on the flop.  I was eliminated in 6th place.
Looking back at the AQ vs 77 hand, I don't know why I called.  If I had stopped to analyze my situation, I would have realized the following:
1.  If I fold, I will still be the chip leader.
2.  If I call and lose, I will move from 1st in chips to 4th in chips.
3.  If I call and lose, I will be giving a large amount of chips to a dangerous player in a marginal situation at best. 
4.  Folding in this spot is not a bad play, the blinds are still low enough that I can wait for better spots to pick up chips.
5.  At best, I am a coin flip.  I could very easily be up against AK in this spot.
All of these reasons should make for an easy fold.  I really have no idea what possessed me to make the call in this spot.   If we had made the money already and I was just trying to move up the pay ladder, I would be ok with this play, but it was still early in the tournament.  I am very unhappy with how I played this hand, and will definately try to avoid these situations in the future.

After this tournament, my bankroll is at $105.19.