Sore right Knee right side.

I am training for the Newtownards half marathon and this morning ran the route at an easy pace to gauge how i will run it on the day. Took it easy enough 1hr 45min. Although around the 9 mile mark I noticed a slight pain in my right knee on the right hand side that gradually increased then subsided then came back again but it wasn't with every step a bit like a severe cramp. This continued on and off until the end of the run, at a couple of stages i thought i would have to stop as it was causing me to limp quite badly. at this point i'm guessing this is not good. Its been a couple of hours from the run and i feel it when im walking and again causing me to limp. can anyone help? The race is on the 24th of June and its very hilly. this will be my first half marathon although i regularly run 10miles plus. please help....

Get some ice on it nstcl.  No idea what you've done but thats the best course of action until you see how it pans out...

Thanks, Iv'e iced it and rested it from Sunday but every now and again it comes back throughout the day. i'm a bit hesitant to run on it yet in fear of doing more harm. one minute it feel ok bun then it comes back. i worried about race day approaching on the 24th of this month,