The first step is to not panic. Other people, people much less capable than you, have survived worse. Get a hold of yourself, you’re not dying.
Next you will want to call mom and ask her what to do, because come on, it’s mom. She always knows what to do. Then, of course, you won’t listen to her, because you’re your own adult and being sick makes you emotionally volatile (don’t worry, you’ll realize she was right eventually).
If you have responsibilities, make sure you are a responsible adult and know when to cancel them. You don’t want to get your coworkers sick, and you don’t want to pass out in class. If you have a fever, that’s usually a good indicator that you need to stay in bed for the rest of the day. Of all the things you should do when you’re sick, that should be the easiest.
Drink water. Lots and lots of water. Don’t ask me why, it just seems to be the magical cure-all. That’s what my mom tells me—Sick? Drink water! Broken arm? Drink water! Cold? Drink water!
What always makes me feel better is a nice, hot bath. It’s relaxing, and when you’re done you feel clean, and if nothing else, feeling clean makes you feel less sick. If you happen to not have a bathtub, well… have you tried using the sink?
Eat food. If, you know, your illness will allow. Don’t starve yourself. The advice I heard is to eat when you’re hungry. I don’t think you’re actually supposed to starve a fever. Then what energy will you have for fighting off the sickness? Chicken noodle soup is the traditional soup for sick people. And, really, it has good reason to be.
The last step is to call mom again. Listen to her, I’m sure she can give you much better advice than I can.