Should I be worried?

I think I’m starting to become burned out. I used to be a straight A student and school wasn’t really hard for me. However, I’m in my second semester of the nursing program and last semester I received all B’s except one A. I feel forgetful and I can’t concentrate well. I feel like I finish studying just before one test to get a B or an A on it, then dump out all the info and study for the next test. Annnd repeat. When I try to study my mind goes elsewhere and there’s just so much information I feel like I’m going to explode. Even when I take time to relax, I can’t really relax because I just think of everything I have to do. I’m sleeping horrible lately and I think that’s why I don’t do as well on my tests. At lot of the information I miss is not knowledge based, but critical thinking based. I feel like everyone understands and remembers things, and I can barely even remember simple things like the difference between acetaminophen and ibuprofen.