Why do i always feel jittery, nauseous, agitated and generally uncomfortable after meals? this seems to occur no matter what i eat, what can i do?

Abnormal insulin...: I'd recommend you explore this with an internist, endocrinologist or gastroenterologist. Some people have an abnormal Insulin response to the ingestion of a meal. There was an old term, "reactive hypoglycemia" linked to this phenomenon- google it and see what you find out, but certainly, discuss it with your doctor after you collect all the observations & details on yourself!

Jittery After Meals : It is common to experience a hypermetabolic state after eating, particularly heavy, carbohydrate laden meals. Your pancreas is busy pumping out Insulin to reduce your blood sugars, and blood is pooling in your gut. Eating smaller and perhaps more frequent meals might help. Schedule an appointment with your doctor to make sure you don't have pre-diabetes or early metabolic syndrome.