Can A Doctor Confirm A Miscarriage Just Four Days After A Missed Period, Especially With Hashimoto’s And Possible Endometriosis?

I believe I had a miscarriage, but I was only 4 days late on my period.
I need to know if going into a dr to get checked out would tell me if it truly was a miscarriage or not.
I was 50/50 in whether or not I was pregnant.
I have Hashimoto’s Thyroiditis and potentially have endometriosis, so I wouldn’t be surprised if I had a miscarriage.