Travel

I am 19 years old and I have recently started working out again. About two days ago I went for a fast walk with one of my friends and we decided to try running for a little bit. I didn't feel anything until later that evening, but I could feel that the back part of knee was sore in one specific area. The soreness starts just a little above the knee area on the back of my left leg and goes to just a little below the knee area. I have had soreness in that exact same spot in the past however it has ever really bothered me this much. Therefore I didn't really think much of it until about 12 hours ago. It feels even more sore now and I can even feel the soreness when standing, walking and even when I am sitting down and not moving my leg. I can also now feel a slight burning and tingling sensation in that area and also in the rest of my leg, specifically traveling up into my thigh. I'm a hypochondriac and as a result my head is already jumping to a lot of different conclusions. Could this be a blood clot?