Do I have a blood clot?

Ok so I 18 and am not really that active more like a gamer. The problem is I sit on my knees a lot and now my thigh hurts but I am a hypochondriac so I fear blood clot. It doesn't hurt too bad just enough to know there's pain there. There's no swelling and my kneecap is a little red but that can just be sunburn. Other than that it looks fine but I just want to hear your guys opinion. Oh and last week I had a blood test so if that tests that then I really am fine but idk.