Caffeine and dextroamphetamine no effect at 18

Never been a regular caffeine consumer in my life other than soda. I’ve drank energy drinks with ~150+ mg caffeine with no noticeable effect. Yesterday I took 30mg of dextro amphetamine when I woke up off of 7hrs of sleep at 7 am with no noticeable effect other than unintentional jaw clenching. Paying attention was not easier nor was focusing and completing work. If anything I had slightly more trouble but that may just be a coincidence or hindsight bias. Today I took 200mg caffeine at 7am off of 7 hours of sleep with once again no noticeable difference in cognitive ability or alertness than usual.

I’ll continue to take 200mg for a week once I wake up and look out for any noticeable difference in cognitive ability and daytime tiredness. To try and keep everything bias-free, I will sleep around 8 hours every night, take 10 reaction time tests and average them out 1-2 hours after taking the caffeine, and also measure my heart rate. Once the week is over, I’ll have a 2 day buffer zone in case of caffeine withdrawals, and then do the exact same tests for 7 days with no caffeine.

I’ve taken 10mg adderall twice before on separate days with no noticeable difference in the same categories listed as earlier other than the fact that I didn’t fall asleep until 3am (taken at 4pm) I am neurotypical (afaik). Only drug use ever was marijuana 3-4x a week on avg (looking back on it the weed was prob boof ash from carts I bought from a friend) for about 7 months (with occasional 1 week breaks) but I’m approaching 9 months sober. However even before that I noticed energy drinks didn’t have an effect on me.

Now my mind is making me want to believe that I have some sort of resistance to stimulants as I don’t feel any cognitive effect, while friends and ppl take less of a dose that I have and go on and on about the effects/benefits (both caffeine and dextroamphetamine.)

Is this normal or am I an idiot