I've taken Percocet and can tell you the shaky lightheaded feeling is fairly normal. Especially if you don't take it with food. Lightheadedness is listed as a side effect of Percocet.
I'm diabetic now but haven't taken any percocet since being diagnosed, so I can't answer the blood sugar question but I tend to think it's from the pain.
Chronic pain, Depression, Fibromyalgia, Tennis Elbow (both arms), Arthritis (knees and fingers), Diabetes. Ruptured disk L-4, Severe degenerative damage L5-S1, ACDF C5-C6