Yeah, I've got some similar clothes anxiety.
I mean, in high school I figure that's common enough, so it's not too strange that I was anxious about clothes then. The problem is that even now, at 22 years old, I still
flipping hate buying clothes and such.
I'm also not that skilled at buying clothes, even ignoring anxiety for the moment. Most clothes sizes fit me in one way but not another. So like a large is just right on my shoulders but way baggy elsewhere. Meanwhile a medium is too snug on the shoulders but fits otherwise. BLARG going crazy.
Thing is though, the fact that buying clothes is partially a skill can be a good thing. Skills can be improved (theoretically, I'm not one to talk).
Regardless, I'm about to finish training and return to my main job next week. Need new clothes for a solid impression so I'll be buying some this weekend.
Here's to hoping that you and I can both get better at it!