I get dizzy when i stand up, could it be an effect of my adderall (dextroamphetamine and racemic amphetamine)?

Unlikely: Unlikely. But in medicine every thing possible . No reaction to any medicine is impossible. However Adderall (dextroamphetamine and racemic amphetamine) is unlikely to cause lower the blood pressure, which causes dizziness when standing up. Adderall (dextroamphetamine and racemic amphetamine) tends to cause high blood pressure than lowering the pressure.

Probably not: Stimulants tend to cause tachycardia & raise bp--more likely u have orthostaric hypotension from changing position 2 quickly so u don't get enough blood 2 your brain.