could I have won? beginner ish player seeking help

You missed 37. Bb6+ which would've allowed you to win white's bishop. Other than that, he had the advantage pretty much most of the game until you got into that draw.
He was the player playing Black who spotted the move 37...Bb6+ and won the White bishop. White had the advantage almost all the time before that. Well, 43...Bxb6 ruins Black's win as the passed pawns can be stopped.

First of all: congrats on reaching that completely winning endgame on move 42.
It's a shame you panicked and sacrificed your bishop for a pawn there, throwing your winning chances away. You would've won just by playing the most natural move ...Rd7, stopping both passed pawns from advancing.
Being a piece up in the endgame is almost always winning, provided your opponent doesn't have a super powerful promotion threat, like connected passed pawns that are far advanced.
Next time you'll get him. You just have to reach a position like that again, take a deep breath, and make calm, solid moves. Don't panic and sacrifice material unnecessarily like that again.