Side of knee pain

Hi! I’m about 2 months out from my first half marathon (April 28th) and on 2/10 ran my longest run of 8 miles and felt great (spent over two months slowly building up to this distance). After four days of rest, I went for a morning run, and 2 miles in felt sharp pain on the outside side of my knee, partnered with some achiness. I stopped and rested with some lingering achiness when walking downstairs. Did a HIIT and lifting workout a few days later with no pain.

Now a week later tried my first run back and got 2 miles in before the pain level increased from a dull ache to some sharp pain; I also felt it a little more at the front of my knee as well as the side. Stopped running and rolled out/iced and my knee feels fine now. Unsure of how to proceed and still be able to keep training for the half in April. Any advice would help, thank you!