Is it normal that coffee makes me sleepy?

I think your coffee may be too strong.

you maybe have reptilian blood

Caffeine affects people differently sometimes. It's meant to be a stimulant but often I find it makes me sleepy too. I think it's a fairly normal thing & depends on when you drink it during the day.
If it makes you REALLY sleepy though, like if you feel an intense urge to nap whenever you have it, I would see a doctor.

I heard that feeling tired after consuming caffeine is a sign of ADHD.

I'm not sure if I love the new short posts because they're fast to read, or if I hate them because they seem like spam.