I have been feeling a lil dizzy headaches and tired could this just my allergies or somethin serious like brain tumor or aniexty and stress

Yes and no: It is impossible to correlate your symptoms with a disease based on a sheet description. Please, go see your doctor.

Cannot say: No way anyone can tell what's happening with the information you provided. Odds are in your favor of not being a malignancy but you need to see a doctor and be properly evaluated. Hope you do well.

First please have a complete physical exam by Doctor to know if you have an illness. Please see a Clinical Psychologist with expertise in multiple types of psychotherapy for a diagnostic evaluation and for help. This will help you to know if you need medication from a Psychiatrist.