Lost my Queen, Now What?

In this game, I was comfortably ahead, but then missed a discovered attack on my queen. I went from ahead to behind in a flash. Now what? It was as much a psycololgical blow as it was a chess blow. My initial thought was that I had lost the game. I continued to play on and through some good moves of my own, and a few key opponent mistakes, I saved the game. I could only wonder if my opponent was affected by winning the queen and lost sight of the need to continue to make accurate moves.

Black turned over the lead to white around move 23. Being ahead in material can produce a carefree feeling. Well and now at move 37, the best black can do will make it mate in at most 7 for white.