I developed a Stutter suddenly and no one knows why

I developed a Stutter suddenly and no one knows why Up until the age of 13 I didn't stutter at all, I spoke clear as crystal (well almost I attended speech therapy in grade school for my inability to pronounce 'S' words right but this was fixed by the time I was ten) Then one year I began blocking on words, being actually physically unable to say certain words, this lasted a few months until I began to stutter severely. It's been a decade now and nothing has changed, I have good days and bad days, but it doesn't seem to be anxiety-driven like most people think it is. The doctors don't seem to know what happened, and I didn't go through any physical trauma to cause any brain damage. I just live with it now, and I hate it, it makes me sound awkward, it ruins any joke I try and tell, and it makes ordering food or asking any questions difficult. I'm a grown woman and I've learned to just accept that this is a part of who I am but I'm not happy with it, like I'm sure most people are. I was just wondering if anyone had an experience similar to mine. Looking up possible causes for stuttering usually talks about children who are born with it/grow out of it eventually, and I know its mostly men who develop stutters for some unknown reason. I just want to figure out what caused this sudden shift, since maybe if I know I can look into how to fix it, or at least get some closure for why this happened to be so suddenly.