cool website to check out
You may already know about this site - have you been to www.unassistedchildbirth.com?
Generally, people do not like to hear about unassisted home births. They will assume you're crazy or don't care about your baby. You might try saying that you were trying to get to the hospital but the birth just happened so fast, and see if people are more willing to help you.
You may very well have to write the governor. I guess if you're considering future unassisted births, you could get your pregnancy confirmed at a doctor's office and save the documentation, or take a film of the birth.
I was born at home unassisted, as well as my younger brother, and we both had no trouble getting birth certificates. That was in Oregon, though, and I guess my mother was seeing a doctor. (My parents lied and said they would call him when they were in labor!)
After I saw that site, I wanted to have an unassisted birth but I knew my husband would never agree, and I ended up having to go to the hospital anyway. Congratulations to you!