Caffeine is also a stimulant, so you’re kind of double dosing it (except that coffee isn’t as potent as Adderall, so it’s not double). I don’t have ADHD, but when I take Sudafed (also has stimulating properties) and more than one cup of coffee, I get nauseous. Or anything stimulating on an empty stomach can make me nauseous.
Definitely talk to your doctor about what’s going on, so they can help you resolve it.
ADDconnect Moderator, Author on Parenting ADHD, Mom to teen boy with ADHD, LDs, and autism