It seems you're looking to describe two different feelings, and there are many ways to describe each.
You could also use any number of physical reactions that happen when you are nervous or excited - "My heart raced". "My hands were shaking". "My palms were sweaty, knees weak, arms heavy" "My adrenaline surged" or the more extreme "I pooped myself", but that usually means fear, not nervousness.
Similes - "I felt like a kid on Christmas"
Metaphors - "I was a kid on Christmas"
Other similar feelings could work as well - "I was in love (with whatever was making you excited)." "I soared through the sky" "I felt trapped." "I froze."