Have you noticed anything in particular that has caused this rise in scores? More putts than usual, poor iron play, a few "chili-dips" or sculls around the green? Drives leaving you in the woods and water? All of the above?

If you usually shoot low 90s, then taking one extra shot, every other hole, will put you into the low 100s. For me, those extra shots usually come from poor chipping or poor drives. And both of those come from loss of concentration on the shot at hand.

Try to isolate what has gone wrong, and work on that. It may be a mental thing - stop fixating on the previous bad shot that you can't do anything about, and think about making the shot you have in front of you.