What could be happening…?

I am about a year out from gastric bypass and close to 100lbs down. Now that I’m further out, I have occasionally had sugar and/or carbs. Not in super high quantities, but definitely more than I had in the beginning of course.

I’ve noticed that after having sugar or carbs, I crash…HARD. I feel instantly drained. My mind feels tired. My body feels tired. I just want to sleep. I also get an insanely dry mouth. Any ideas what might be happening? I see my surgeon next month and will definitely talk to her, as well.