make a (big) thing (out) of (something)
To exaggerate or put too much focus on a minor issue and make it seem like a major one. You got one B and you're acting like you're failing the class. You're making a big a thing out of nothing, if you ask me. Let's not make a thing of this. It's just a minor setback.
make a thing of
1 regard as essential. 2 cause a fuss about. informalmake a (big) ˈthing of/out of something
(informal) make something seem much more serious or important than it really is: It was only a small mistake, but he made a really big thing out of it.