When will it end?

So I have been sick this week and did not run wednesday and thursday but I was feeling good so I went for a 6.5 mile run outside today. It is a beautiful day outside. I was doing really well when at 4 miles my right knee started hurting so I slowed down and tried to work it out and then had to stop and stretch it but it just kept getting worse. So I ran my 6 in just over 54 minutes but I had to walk the last 1/2 mile home. At least it isn't my left ankle:)