It normal to be shaky and low in mood even upset after a nap?

Sometimes after a nap I wake up upset dizzy and all around sick with awfulness. I notice this more if I have eaten first and especially if it is some sort of sugar. I can't seem to snap out of it easily. It makes me feel like it could have something to do with high or low blood sugar. I get restless legs at this time as well. Anyone else experience this???