Being so tired that I can't stay awake?

Diagnosed as AchR+/SFEMG+, generalized MG.

I was on the couch after dinner, trying to study a bit. Suddenly, I just couldn't keep my eyes open, so I fell asleep. I slept fairly well last night, and I have only done light chores inside today, and some grocery shopping.

I have haf this happen earlier as well, but it has been rare, and mostly when I have overexerted myself a lot. Lately, it is almost every day, no matter how much I sleep at night. I just cannot stay awake, when I have these spells, which makes it scary to drive for more than really short trips.

Has anyone else experienced this? Could it just be a MG flare, or should I try to look into it more?