How did black lose?

I'm trying to figure out what went wrong for black this game, I found after 13.Qf5 white seems to have a forced win already despite the black king being surrounded by his pieces, also if 8.e6 by white was a valid idea or just gives up a pawn for nothing. Long story short I'm confused and want to know whats happening, it felt like white out of the blue was super winning which to me for some reason was unexpected. 

Well just count the pawn moves vs the moves that actually develop pieces. And despite that you don't actually have any central control with your pawns.

a6 c6 and d6 with one 1 piece developed? White has two great central pawns already and bishops have lots of options. You need to fianchetto the bishop with the pawn moved to d6 but don't even start to? Nc6 controls the e5 square rather than c6.

I think the Pirc isn't the easiest defence to play because you have to be able to prove compensation against central control. You can't really afford to waste time.

Black didn't develop his pieces and he didn't fight for the center. 

This is what you would expect to happen when black plays like that. 

If you were black, answer 1.e4 with e5 for a little while. You need a foothold in the center to stop you from getting blown away like this. 

As others have said you didn't pay proper attention to the centre. Specifically, you allowed white to play e5 and put your knight on f6 under pressure. 

The way to have fixed this would be to meet 1. e4 with 1. ... e5. 1. ... e5 is the most natural move and I wouldn't worry about playing fancy openings such as c6 and c5 (as responses to e4) until you have mastered the bread and butter 1. e4 e5 openings. 

wasn't great but on move 7 you were not totally dead given your level of play (but its not good either).   Dxe was probably playable if you had fought back hard after.  But by move 9 when your king is marching out into the fight by himself, its over.  Never let your opponent force you to recapture with the king this early, as losing the ability to castle and risking moving the king to an exposed square just opens up too many attacks.    Looks like you play mostly fast games.   Consider playing slower until you understand a lot more about the game; playing fast is not a good way to make progress (enjoy it now and then, but you also need some deep thinking time). 

Ok, the weakness of light squares mixed with the lack of development killed black. What appalls me is 8. Nf6??. Dang! You cannot castle, and you have used a piece you've already developed

The Pirc is not an opening you can just "Wing it." 

Don't get me wrong. Black can get a good game with it. But he needs to walk a tightrope. 

Stepping off the beaten path with 3....a6 is a good way to get yourself in trouble.

So I would recommend you either find a different opening, a safer one. 

Or, actually learn the Pirc. ---  Which sounds suspiciously like work. 

(Yuck, right?)

Black is pretty dead/ very unpleasant since move 3. .. a6.

Please learn opening book/principles.

Just as a side note for everyone I was actually white this game