I am not diabetic but i always feel low and dizzy when i've eaten. my blood sugar can be 130-40mg/dl and can then drop to 50mg/dl throughout the day?

Doctor/lab: If your glucometer documents this sort of drop it isn't normal. A home glucometer isn't necessarily accurate. Your findings need to be evaluated by your doctor and confirmed by a lab to determine if an ensuing work-up is necessary.

See your Dr.: Just curious how you happen to be checking your bs. You also need to have your hb1ac checked to see what your average bs is. Your doctor will probably also order a glucose tolerance test. There may be some medications that could possibly help you avoid developing full-blown diabetes which sounds like you could be developing. You need to get checked asap as complications could be developing.