Hip Pain- Marathon Training

Hello! I’ve been training for my first marathon in Houston in January. I did my first 16 miler run two weekends ago. I felt good during the run, but the days after I had terrible hip pain on my left leg. The pain on my left hip has not gone away. It hurts when I walk and run. I had a 10 miler run this past weekend. I took it really slow, but noticed the pain during the entire run. It got a bit better towards the end, but I do notice my gait being really off. I have been icing it, doing mobility work, and I also started going to PT. I guess I’m just looking for feedback, or if anyone has been trough a similar situation… what helped you ?

I am getting a bit nervous as I approach 18 and 20 miler runs these next few weeks. I am feeling a bit discouraged and fearful, as my marathon is approaching. Appreciate any help in advance :)