What could these symptoms mean?!

Yesterday in class I was totally fine, then about an hour in I suddenly got shaky hands,sweaty palms, a much faster heart tate, and this weird faint feeling in my head. I hadn't eaten in a while but I'm used to this with my schedule. I also work nights so I'm constantly rotating my sleep scehdule. It went away after 15 mins or so but what could it be?