I'm just about out of my plantar fascitis, having dealt with it for about the past year+. Mine came on slowly last spring, which I attributed simply to my feet feeling tired and sore from being on my feet many more hours than normal in coaching, and likely in bad shoes. Once I realized what was happening it was too late. From the time I started treating it until now has been 12 months, with the first 4 months being the worst. I'd say since the New Year I've been progressing steadily to the point I no longer consider it now but still feel it occasionally.
I did not consult a doctor because it wasn't something that hindered my life too much, just more of a nuisance. What was useful, for me, was to be aggressive with it early on. I did the ice treatment nightly, did calf/foot stretches with rubber bands, and even bought an overnight brace similar to a sleeping boot. Once I got to a point where the pain was no longer increasing I was less aggressive and simply let it heal its way back. One of the bigger things for me was changing up my daily shoe rotation. No more nice but uncomfortable work shoes, and was allowed to go to a softer sole which made a ton of difference. I do think getting rid of shoes that are old that have lost their cushion is crucial, as is replacing worn insoles.
I realize my case was likely mild, but there is hope. Eventually one day you don't even think about it anymore, and then you realize you're done or almost done. Best of luck to all. It's hard to understand how much you under appreciate simple health until you get to a spot where every step brings pain.