Blunder, and loss. Was it the cause?

Hi, here's another game I lost, and I'm trying to figure out what exactly happened. The blunder, of course, played a big part in it. I'm black.

I basically stated the reasons I lost in the game, but would like further feedback. There are a couple of questions in the diagram. 

"I didn't actually realize he was attacking my rook." Why not?

12...c6 may have been better for you. 

the theory on the closed ruy goes 5.. Be7, indirectly defending by closing the e-file. 6 Bxc6 dxc6 Nxe5 Nxe4 is completely safe.

as played i think that Bxf2+ is actually a huge mistake in these kinds of positions. white gets a strong center, open file for the rook and great piece activity. after that, well, life sucks.

this bullet game is an example of what i mean - it's surprisingly hard to find improvements for black (actually engine says that black is already lost after 9.. d6 - about +3.5 score)

I'm curious why Black didn't play 6.Nxe4 ?  Your 5.b5 move deflected White's bishop from attacking your defender of e5, and so that was your window to take on e4. 

8.Bxf2+ was a disastrous blunder, since Black had just sacrificed an active bishop for no compensation.

Samir, the reason I didn't play I didn't play Nxe4 is because after white plays Re1, he wins the pawn back, with what seems like better development to me.

8.) Bxf2 was not a disastrous blunder because I would have lost material anyways, with white forking the knight and bishop with his pawn.

Ben, I'm with you on your first point.  You're right about the awkward development after 6.Nxe4.  However, there had to have been a way to preserve your material.  I don't think the bishop sac was necessary.  

Let's say we allow the fork to happen.  You start off a piece up after 8.Nxe5, but return the piece immediately after White recaptures whatever piece you leave behind.  

For example:  

8.Nxe5 , 9.d4 Bd6 , 10.dxe5 Bxe5

There's no material loss.