Weird feelings.

So I just turned 18 a month ago, and I just got over my first period of being 18. And it so far has been one of the worst periods I've ever had. During my PMS I had the worst anxiety, I could barely go out and do anything. Then when the period hit, it was soooooo incredibly painful that I felt the need to vomit. And I normally don't feel like that during my periods. It's been a few days since it ended, and ever since I have been getting nauseous for no reason. Each day it has been getting slightly more worse, and I had to miss classes because it. I keep thinking it's my hormones going crazy, but I don't know. I'm so frustrated, I want to feel like my normal self again. Does anyone know of what's going on with me?