MILD and some moderate anxiety is a normal response (the kind that motivates us, or signals our attention to something) But there are the more severe types, panic attacks that are more disabling.
I suffered many years with anxiety that went undiagnosed. Got worse in nursing school. Wasn't til my Psych class that i learned what a panic attack was, and I was even having them in my sleep (every few nights I'd wake up gasping for air, and every morning a major headache that felt like a hangover, and of course the classic major palpitations, and dizziness, etc). Since starting anti-anxiety drugs, I haven't once experienced that. I've exercised all along, and always take long hot showers, which i believe help, but none of this thought-changing helps while sleeping. Sometimes for sleep, it did help to set the sleep-timer on my tv and watch some silly makeover show or something.
Best wishes to you in school!! I am struggling along with you. I hope you find a way to cope that works for you.