Just got my first job! Now I’m breaking down : ADHD

I suck in commitment. Barely serious in a lot of things. But i just got a job. A dream job i had since i was a kid. But seeing my boss’s email about contracts and prices scared me. My body just feels like it wants to throw itself out the window. I spent the whole day reading the contract, barely absorbing the contents, i barely ate. Im happy about the job but god i feel like crap.