Arch Pain

Hey! So I’m currently upping my mileage training for the Chicago marathon. I ran 17 this past week (longest I’ve ever run, longest prior was 14). I felt so great/pain free during the run. I went to a pretty tough yoga class on Tuesday after two days of pretty much completely resting & afterwards, developed some arch pain in my left foot (I really can’t tell if it’s more plantar fas or post tib esque just by googling). I massaged it out and woke up with some mild swelling. I can walk comfortably, hop/heel lift on it… but it’s painful (kinda feeling like a tight archiness) and still seems a little inflamed compared to the right. I’ve worked with a PT in the past for hip issues so I looked up some resistance band foot exercises and plan to incorporate those throughout training. Should I replace my long run this weekend (16 mi) with some sort of low impact cross training? Let me know your thoughts and maybe ease my anxiety a bit if able (I can never tell when to be nervous or run thru little aches and pains). Thank you so much