I've been really worried about tomorrow
That's interesting. What are you anticipating tomorrow that is worse than other days?
I have studied, but I'm still worried about my math test.
It's okay to be nervous about your math test, but it doesn't help to worry about something that you have prepared for and can't do anything else about. Trust in your preparation and knowledge and let things play out as they may.
I guess you are right. I'm going to go to sleep now.
Have a good night, and you got this! As long as you've studied, you are going to do well on the test so don't stress, that will only make you feel more anxious.