Help with my last game

Can someone take a look at my most recent game against “tickelpickel”. The game started with queens gambit declined, which I don’t know how to play. White had me by one move pretty much the entire game, and then somehow things shifted and I easily queened a pawn. I can’t figure out when or why the transfer in advantage or power occurred. Could someone help me pinpoint that? Analysis also showed I had 2 missed wins which I can’t seem to figure out either. Just some feedback on the game would be great. Maybe ideas on queens gambit declined? I don’t know how to attach a game to a thread either or I would’ve done that. Maybe tell me how to do that as well? Thanks for any help!