Marathon...down the drain :(

So sad. So I had begun training for a half marathon in February. I was getting pumped...I really was. I was so excited to be working towards a goal, I was finally enjoying running and I was building my endurance up. And then today, it all came crashing down :(...my poor little left knee decided that it couldn't take it anymore, that it didnt want me to run the race, that rather it wanted to swell up like a big balloon and hurt really bad :(. So my dreams of being an amazing champion marathon runner are shattered...back to square one, I'll have to find something else to work towards.