You should only be mildly annoyed. And then only if you needed a 5 for credit.
Perspective is so easy after the fact. Try using it in the moment though. It won’t seem bad at all.
Looking back, I have a very specific advanced degree. I use it in a very specific niche area of a larger niche area. My worst grade in that final niche degree was in the area I specialize in now. And I’m actually very good at it. One grade means nothing. Have fun this summer and don’t let it impact even one more second of it.