BUST A BLOOD VESSEL?

[Deleted User]

I am a charity supporting runner with aspirations to do a second half marathon. Having run 11 miles early one morning I felt smug - it went well, I felt good, tired but no pains. Did my stretches as normal, up to bed with a cup of tea for the missus, and showered. About an hour after the run finished, I experienced an excrutiating cramp-like pain on the inner aspect of my left thigh accompanied by a swelling about the size of a tennis ball. The swelling was slow to disappear but did so after a few hours but I still ache there nearly a week later. Two days after the run a livid bruise appeared, stretching from the top inside of the thigh to half way down my calf. How can running cause such a major bleed? What did I do wrong? Has anyone else experienced anything like this? Can't run now, fed up.