Definitely go to your doctor and get this checked. Low blood sugar temporarily makes you confused etc but if you are more permanantly confused it could be something else. Are you able to purchase a meter or ask a friend to borrow one? When you feel 'strange' test your sugar and see if it's low. It may well be that you are developing diabetes - if you feel lethargic after eating this might mean your blood sugars are running high, but I'm no doctor. But I really do advise to go to your doctor to have this looked into properly!