Review for Plantar Fasciitis

I have plantar fasciitis now for 4 months and I'm in agony I've had to go on a leave of absence for about a month now because I can't stand never mind walk but it's not helped, I was given an injection but that didn't help which surprised me because in the past it helped I believe it's because it was given in the side of my foot instead of in the heel directly. I'm getting orthotics plus I wear slippers with memory foa. Instead of going barefoot. I am miserable and don't know what to do.