I looked at one game, with Lucab, and you lost a knight because it had nowhere to go, but if you back up a few moves before then, the white knight came up to threaten c7 and you brought your queen back to protect. At that point your knight was dead meat. If instead of moving queen, you move knight to a6, it gets it out of immediate harm and protects the c7 pawn at the same time and your queen can stay out in the fray instead of hiding out in the back row where it has no power. Take a look at that game, ok? It helps to see when your pieces are going to be in deep do-do like that knight. You want to make sure all your pieces have a hidey hole in case of attack or some kind of counter-attack which in your case there was no counter once your queen moved back home.