Shins and ankles started hurting

In januari I started a marathon plan on Runna to run my first marathon by the end of may. the app calculated my pace for the race to be 4.30/km based in my 10km pb at the time. training was going absolutely perfectly until 10 days ago when suddenly during the easy runs I started feeling my ankles kinda hurting. since then I’ve made sure to pay attention to my form and not to go too hard but also tried to keep up with the expected pace for the long runs. surprisingly it was never during the long runs that my ankles and shins started to hurt but often at the end of the easy runs that followed.

I don’t really know what to do now. do I just rest and not run at all for a while to prevent hurting myself more? do I walk to keep moving?

I also don’t really know what the issue is. The shoes I’ve been using apparently aren’t really made for long distances (I use the Nike revolution 7 or something similar to that). maybe my body just isn’t used to the training volume/intensity given it’s my first time going for a marathon. I made some videos of my running form and what I’ve heard is that usually overstriding leads to pain in shins but I definitely don’t do this. I’d share the video but can’t figure out how to do this on Reddit.

is this usually a form issue, a shoe issue or just inexperience? what should I do next?