My question involves name change laws in the State of: Georgia

So, my last name was changed back when I was 15 or so, in example, Ann Spence to Ann Dean. I was taken to some government place where I was told to sign a form or two that would change my last name. Not really knowing any better and with all four of my siblings having had their names changed to our 'supposed' father's name, I went through with it.

I don't know how things work here in Georgia, but he had no legal custody of me at the time. My aunt had guardianship of me my entire life. She was never informed of this so I don't know if it was 'legal' or not.

A paternity test was never done either so I have no idea if he's my biological father or not.

So, I want to have my name changed back to my birth name. Is there anything to be done about the possibly shady means he took to change my name? Or do I have to go the normal route of how its done here in Georgia for a name change?

I also have to get a new birth certificate for my driver's license(they wouldn't take the one I have currently), and while filling it out do I have to put this guy's name on it as the father? VitalChek says gives me an error about my last name being different from my mother's if I don't, but hasn't stopped me from continuing the order process. I haven't bought it just yet until I know for sure though.
Also, I was born in Chicago, Illinois, if that matters any.