College Health Center Charged Me $400 for a Simple Checkup

I just need to vent. I’m an undergraduate student at my college and I went to the health center a few months ago because I have bad health anxiety and was worried about my thyroid. I have a fear of autoimmune diseases. All the doctor did there was check my pulse and look at my thyroid. She also looked at my old tests from my primary doctor to just look. That’s all she did. I thought that students were able to have free appointments but apparently 3 months later they are now trying to charge my insurance $400. I’m hoping that this is a mistake. Is this a normal thing that’s supposed to happen? It’s a private college but I still feel like the price of admission should be enough.