Could this game have been drawn?

This was an OTB game, 90 minutes with a 5 second delay. The game ended on a blunder, but I was lost even before the blunder. After the game, my opponent said I should have doubled rooks on the seventh rank and secured a draw that way, instead of using a rook to defend a weak pawn on e4. Although I didn't think of that, I suspect I should have drawn this game anyway. I have not done the computer analysis.

Yes, you should have at least drawn but these games are not easy. Except for the last blunder, you did well.

No, this was USCF rated. There are not a lot of FIDE-rated tournaments in the US.

Move 39 you "knew you were lost and mentally checked out", when in fact it's a draw. Play Kf5 and it's 0.00.

I think the lesson here is to not give up.

It's 0.00 for a computer. For a human it's much easier to play for black.

Chin up, you will do better next time. Blunders happen.

You were not lost before the blunder. You were a pawn down, but his king was passive. You had some advantages there. One is that his king is prone to checks from the side (in some cases mate would be threatened), and there are some chances to win one or both of his kingside pawns if he goes for b3 pawn. Second, his rook is in front of his b pawn.

Not enough for a win, though sure, you would have to be careful and one can lose a game like that easily.

Is it? How do you even play for a win with black? Black is up a pawn, but white is "up a king". There is no way black is better here.

39. Kf5 Rxb3 40. Kxg5 b4 41. Rb6 Kf7 Rb7+ and now what?

Or maybe 39. Kf5 h6 40. Rb6 Rxb3 41. Kg6 Kf8 42. Kxh6 equal.