Ok guys... I know this is stupid, but I've got this sudden fear of a blood clot forming in my leg. Recently I've been sleeping alot because it's summer... and i'm on break. When I get up to walk around, the back side of my knee kinda goes numb.. and it goes up the muscle in my leg towards my butt. It goes away.. its not tingly like when your foot falls asleep. I'm sure it's nothing serious... I mean I don't have any swelling I don't think and I'm in good shape, I'm not overweight.. and I've never had any problems.. and it's not a pain. It just made me have an anxiety attack and now I feel sick.. :( Now every pain I get makes me freak out. Please give me some insight.