stimulants (like caffeine, ritalin) make me sleepy! what is wrong with me?

hello,

after I drink coffee, I have to take a nap! I know it sounds weird, but it's unfortunately true :-(
Once I bought an energy drink and instead of feeling more energetic… it made me go to bed :-(

Recently, I found out that I have ADD and I've begun taking ritalin, a stimulant. Well, it makes me sleepy! I think I will stop it, it's horrible.

I remember a few years ago, I suffered from some anxiety and the doctor prescribed me Xanax,…. well it didn't work at all, I had much more anxiety after taking Xanax than before so I stopped it.

There must be something terribly wrong with the chemicals in my brain :-(

Has anybody ever heard of something like this?

Thank you in advance.