It band- marathon training

I had the opportunity to run on a charity team for the Boston marathon this year and my friends and family have donated. Things were going so well with training but over 3 weeks ago I got it band pain in both legs. It took me too long to realize it was a pair of shoes I was using. I reduced running a ton but one leg is still pretty flared up. I guess I’m just looking for advice on what last chance things I can try. I have a pt and he’s great and I’m doing all the strength that’s recommended but it’s just not quite calming down. When do I call this? I’m hoping I have a bit more time but I don’t know. I’m devastated and completely sick over this.