u/Extreme_Ad8051

Have you ever had a position like this? I stumbled upon a preschool chess tournament at my college and decided to play someone stronger. It started out standard: pawn e4, pawn c6, knight e3, pawn f5, bishop c4, knight f6, o-o, I don't really remember what happened next, and then I lost with the classic checkmate rook + queen. He played half-heartedly and as passively as possible, but somehow he put me in a situation where any move I made was useless or worsened my position. I still haven't figured out where I blundered; I should have written down my moves. Criticism and advice are welcome.