you're lucky if white had done Rb7 for move 50 you would have lost but your endgame was good
poor opening ended well

you're lucky if white had done Rb7 for move 50 you would have lost but your endgame was good
the game was decided long before Move 50, so I find it difficult to agree with any radical move for white after move 46

Looks like White could win with 40 h5. And White might be able to pull a win out of the position after your 44th move with 45 Rb8 (or maybe 45 Rb7). It looks close...but at any rate, he shouldn't have to lose.
perhaps you're right, yet I'd like to down estimate 40 h5, and actually I have anticipated this move, which, one way or another would have helped me to unleash my bishop or king after exhcanging pawns and weakening the advanced and dangerous f pawn (whic was protected by two pawns let's say.
move 45 Rb8 seems more serious, and yes I'm lucky white didn't figue it out, yet, I would have left with two pawns and a rook against a rook and a knight, which I would have been lucky to make it to a draw.
finally, thank you guys for your assistance, but what would you say about the opening, what sould I've done to avoid the difficult situation in the midgame?
I think I screwed up in the opening a little, pulled my self in the mid game, and was saved in the end-game. first enjoy the game and learn from my mistakes, next please give me some piece of your mind on my general strategy