If you can, try to position a pen or marker into a vice that holds it steady and upright. Then move the paper around under it, as if you were FMQ'ing to re-train your brain. When we doodle, we move the pen around the paper and I think when we start on FMQ our brains want to do what they know and it causes a dis-connect.
That said, the best I can do is follow traced lines and do loopty loops but it's a million times better than it was a few months ago. I think there might be something to the wine suggestion. Everyone on here swears by it. If all else fails, there's always that.
;)
Good luck. We've all been there.