Make sure you have drank enough water! That's always my first go to, I grt dehydrated wayyy quicker than other people. Then check your temperature, If I get too hot I will become extremely dizzy so sometimes cooling myself down can help. Have you eaten? Do you need more sugar? Both of those can make me feel dizzy if I haven't had enough. A fizzy drink (soda) or chocolate bar can help give me a boost until I can eat something proper.

I know this post is tagged fibromyalgia but have you looked into a POTS diagnosis? I'm also in college and have pots and fibromyalgia, what helps me is drinking a lot of water, compression garments, making sure I'm eating consistently (that has been a real struggle for me with college), and also the medication zofran