it may just be normal. im diabetic and there are times when i tremble for a whole week. but if u r really unsure about it, ask your doctor.
You don't give us much information to work with. Trembling hand/s or feet/s, or arm/s or leg/s, or all over? Tingling perhaps? What kind of diabetic are you - type 1 or type 2? How well are you controlling and managing your diabetes? Have you or are you apprehensive about something that has or is about to occur?
As you can see there are way to many unknowns. You could be developing hypoglycemia - low blood sugar, or developing some other health issue. Suggest you call your doctor immediately.