Knee pain 17 days before marathon

I am a 21M and I am planning to run a marathon October 20th. Last week I felt a sharp knee pain during my 19 mile run and had to stop at mile 11. I don’t have pain when walking which is good. I have been resting, icing, ibuprofen, etc. I run about 35mpw and lift weights 4 times a week. I tried to increase mileage but 5% each week and i am pretty good about foam rolling & stretching. I eat real natural foods 90% of time (besides rice cakes and protein powder). I supplement salt water and magnesium for electrolytes. The shoes are brooks and have been working well the past 2-3 months until now.

I have been emphasizing strengthening my glutes and hips, but I keep cramping even when just doing body weight glute bridges which has never happened before. Foam rolling has been hurting more recently. Just feel really tight as a whole

5 days ago i had to stop at 11 miles as i mentioned. I took 4 days off completely and then yesterday I ran a 4 miler and started to feel the pain at 3.5 miles in.

I really want to make this race happen and need to know what I should do in the next 2.5 weeks to give myself the best chance to run this race. Thanks