Question about prescription access?

I’m sort of in disbelief right now. I have a new GI since graduating college and moving. I have a prescription that I take on an emergency basis. I just took my last dose of it on Friday. I contacted my new GI for a refill and he says he doesn’t prescribe that medication.

Is this really a thing that can happen? I can be on a medication and need a refill and the doc can just say “nope I don’t prescribe that”?

How the &%-# am I supposed to get my meds?