Someone could be using your insurance to receive care.

Can you log in and see all your past appointments and how much you've spent on care in the past year and make sure no one else is using it?

Call your insurer. Ask to speak to the fraud investigating unit.
Get it documented. You will feel better. It's possible someone stole your insurance info.
If you do this you will be fine and won't worry

So update: I tried calling the doctor office the past two days and wasn't able to reach a live person. Last night, my phone received an automated voicemail appointment reminder. I was able to reach someone this morning and the appointment was definitely for me for a well woman exam, made on Nov 20 for tomorrow. They had my DOB and insurance info as well. I'm totally weirded out.

Would something like this show up as identity theft or just a computer glitch?

Yes, just call them before freaking out. I was emailed an appointment confirmation once from a dentist in another city. It turns out the confirmation was for another woman with my name. My email address is firstname.lastname@gmail.com, and they mistakenly thought that was her email address.

Just call them and tell them you never made an appointment. Don't get ahead of yourself.

I wasn't sure how to word this in the title. I'm currently pregnant and seeking care from an OB. Last night I received an email from a practice I've never heard of IN ANOTHER CITY 6 hours away with my name in it asking me to confirm my appointment for later this week. I do have an appointment today with my OB here but it's a different date/time and the doctor listed is one from that practice, not mine.

And now that I think about it, when I was last at my OB, they somehow had UHC listed in the computer as my insurance when I've always had BCBS. The only thing I can think of is that both practices use the same "patient portal" from Athena Health and somehow my information has gotten mixed up with someone else. So now I'm freaking out, wondering what if my actual records have been mixed up too? Has this happened to anybody else? (FYI- I don't live in DC area).