Why do i keep tensing my body when excited or happy?

I’m 20 years old and ever since I can remember I’ve always had this habit of tensing my body when i’m excited or happy over something.
The only way I can explain it is that it’s like I can’t quite feel or express emotions associated with happiness without tensing and I usually get the urge to tense up like this if I’m doing something exciting like going to a concert or thinking of scenarios that make me happy while I’m trying to fall asleep.
It never happens for long though, maybe a maximum of 10-15 seconds.
I suspect it may have to do with my anxiety and the fact that I’ve dealt with depression since I was a child and was never fully able to express feelings of happiness. Or perhaps it’s a psychological habit that I developed as my way to hold onto and savour small moments of happiness before they disappear.
I’d really love to hear a professional opinion or from people who have experienced similar habits to mine.

P.s I’m sorry for how badly this is worded, it’s always the most difficult for me when writing about myself.