You are fine. You have $200 of income without any tax documents, which is fine. It is not a gift, not any more than babysitting for your cousin is if your aunt gives you $20. It is earned income.
Lots of people have income that isn’t documented - shoveling snow, cutting grass, babysitting, teaching a piano lesson. Because it is under $400 you do not have to file an IRS return.
If you are still working for this restaurant, keep records of what they pay you.