Why am I tired while on adderal XR (20mg am / 15mg pm) even w/ full nights sleep & normal bloodwork?

Drug effect? . Could be a drug effect. When does tiredness occur? Fatigue with offset is a common problem. That means as the medication is offsetting, one feels irritable or tired. Are you tired when the Adderall (dextroamphetamine and racemic amphetamine) is wearing off? This may not be the right drug for you. Explain your symptoms to the prescribing doctor. Adjustments may need to be made .
Maybe diet & action. Stimulants only help when otherwise well. You need to work out early every day, eat a healthy balance of real foods (not dyes or sweeteners or overprocessed snacks). No smoking. Plenty of clean water and fresh air and sunshine or vit d supplements. Did tests include vitamin levels? Are you taking omega 3s? B vitamins? Magnesium? Could you be low on iron? Ask you doctor.