Here is a game I just had to share with you.  I got my butt kicked hard in this one.  The irony is, I thought I was winning.  Even at the very end, he only had 4 of my pawns while I had 2 of his pawns, a knight, a bishop, and a rook.  Even the computer analysis of the game thought I was winning.  In fact, Chess.com's analysis program called his bishop sacrifice a blunder, but in fact it is was all just part of The Joker's plan.  Next thing I knew, the Bat Mobile had a flat tire, the Bat Cave got blown up, and I'm being carried away in the Checkmate Ambulance. 

Well maybe in move 11 you should have just exchange your Bishop for his Knight.  That should have solved your problem 

Actually your move 13, much better in my opinion would have been K to g7 & leaving your Bishop for your opponent.  After that, move your Knight to c6.

But then again you never saw it coming.  I feel your pain as I have been through it before.  It was stunner for me that left stunned for about 36 hours!

I'm very surprised that 1200 player could find something like Re5!! it's very high level move I don't think I would have found it..
In my opinion the biggest mistake was 13...g6 if you have played Bg6 instead, you would win.
Again on move 16...Rh8 was saver.. But I don't know.. That last combination was weird..

Neither one of us were true 1200 players.  Both of our ratings took a hit because of timeouts.  He had joined a few months earliler and timed out of both of his games, so his real rating was still basically unknown.  Since he came back and started playing again, he went on a long winning streak, and his rating has been climbing ever since.

But yeah, 13...g6 was definitely a huge blunder.  Realized it right away, but it was too late.