I had a pain in the centre of my calf suddenly so I pressed on it and I could feel a knot. It eased off after a few seconds and it dissappeared.  
The leg seems heavier than the other but I can't actually tell if that's in my head. No obvious swelling or differences. I figured if it was a blood clot of that size I'd have some physical symptoms as well.  
I've done alot of exercise in the past week after not doing much for months. My leg just seems heavy and I can't shake the feeling somethings wrong and I hate it. I constantly worry about blood clots and its always in the same leg. I just want to grab a few hours sleep.