I'm not so sure you're as lost as you seem to think. 44...Rd1 45.Rxe2 c7 46.Ba6 is the only move to try for an advantage, and at first glance white seems to have fairly good drawing chances if he can get his knight back to position, probably after 46...c8=Q 47. Bxc8 Nxc8, at which point as long as you can nab his one pawn for your three without getting your knight trapped... well, it's not the easiest defence, but I'd think it looks fairly holdable.
Best Endgame I've ever played

The black king can't get closer immediately either. Surely white can do something about the pawn after 44...Rd1 45.c7 Rxe1 46.c8/Q+?
Scarblac's line looks even stronger, with a probable draw. Black is threatening to play Rf1+ followed by e1=Q, so white has to make sure he doesn't leave black with a move to do that, either by checking the king, taking the rook, or possibly eventually playing ...Kg4 with the threat of some forced mate. How that would all shake out requires more careful analysis

Your move 21 question:
I think 21 Nc5 simplifies nicely. Your knight is mediocre and his bishop looks scary with the open g file. If 21...Ba8 22 Nxa and if he tries something "clever" like 21... Na5, I would swap bishops and then either Rxe5 leaving his pawns messy or perhaps better, Nxa followed by Nb4 and white now has a good knight with access to black's "holes" and any attempt to remedy his situation will straighten white's pawns out.

...44.Kd6 is not really a mistake at all. The position at move 44 is fascinating, I spent at least an hour on it this morning.
First though! Your opponent's biggest mistake was resigning. That position at the end is not lost, it's drawn. He just plays Ra2 and you have a drawn R and P ending, that's worth studying.
Second. At move 44 he's got 44...Kf6!? (threatening Rf3#) It's not actually better than Kd6, but it's probably a better chance for winning, you have to defend accurately, but you can. It gets pretty interesting. Your N is a real hero!

...44.Kd6 is not really a mistake at all. The position at move 44 is fascinating, I spent at least an hour on it this morning.
First though! Your opponent's biggest mistake was resigning. That position at the end is not lost, it's drawn. He just plays Ra2 and you have a drawn R and P ending, that's worth studying.
Second. At move 44 he's got 44...Kf6!? (threatening Rf3#) It's not actually better than Kd6, but it's probably a better chance for winning, you have to defend accurately, but you can. It gets pretty interesting. Your N is a real hero!
thank you for the analysis, I didn't know that was the drawn position, I thought after he'd taken my pawn, I could push forward the pawn, then if he try to move the rook to stop it, then I take the pawn, it would then 1 P + R vs 1 R and I could somehome win, thank for ur pointers, it's open my eyes ^^
I've included my comments, thoughts and questions in the game below, would really appreciate it if someone could give me some pointers, thanks ^^