Why do i feel so naucious?

i am 17 and every evening after dinner mostly i get super dizzy and naucious and get headaches... i am taking some medications birth control, spironolact, tylenol for tension headaches, and lexapro (i have polycistic ovarian syndrome, severe anxiety, and problems with my T.M.J ) i forget to take my spironolact and lexapo sometimes, but one of my concerns is that i mught have diabetes its hereditary in my family and im worried that thats what is causing my nausia.. please help and only serious answers please.