Hi! My Period Is Not Usually Regular But From My

Hi! My period is not usually regular but from my math I believe that it is at least 2 weeks late. For about a week I had the regular symptoms I usually get when my period is about to come but it never came. Now I just feel dizzy all the time and feel like vomiting. I've taken 2 pregnancy tests and they both came out negative. I have been taking aderall for the past 2 months, could that be affecting my menstrual cycle?