Since Adderall is a stimulant drug, it can cause heart palpitations. It can also increase blood pressure and cause dizziness. If you are not eating enough, this could exacerbate dizziness and lightheadedness. Unfortunately, side effects to medications can appear at any time during the therapy. I would discuss these side effects with your doctor and if you decide that you cannot tolerate these effects, you may need to change your medication.
My recommendation is to talk to your prescriber about the symptoms you're experiencing. He or she is better able to determine if this is related to your medication or other underlying issues.
Okay, so not eating right could be a possible cause of the dizziness and feeling faint. Could the heart palpitations also be a cause of feeling faint? Should I be checked for an underlying heart condition?
Adderall is speed. Pure and simple. Something your doctor does not tell you.