I always feel dizzy, weak and low about 1 and a half hours after eating. i've noticed if i ate a chocolate bar or something i feel okay in 15 minutes?

No short answer: It sounds like hypoglycemia (low blood sugar). It can be seen in diabetics but more often, i feel, in people who later will be diabetic. If you are overweight please lose weight. Please see a physician, other things can cause it. If you have diabetes in the family the chances are greater that you will be. If someone has a test meter, when you have that spell, clean your finger & test your sugar.