No, your leg's not asleep.

Could it be something more?

Deep Vein Thrombosis

DVT, or Deep Vein Thrombosis, is a blood clot that forms in a vein deep in the body. These blood clots occur when the blood thickens and sticks together. A blood clot in a deep vein can break off and travel through the bloodstream; a loose clot is known as an embolus, and if it travels to the lungs, can cause a pulmonary embolism or PE. Watch out for symptoms, as they can easily be mistaken for something else. If you get swelling in the legs accompanied with pain , tenderness, warmth or redness, talk to your doctor. The risk of getting DVT when travelling over 4 hours is increased, so here are some tips to help you prevent it: Move around at least once an hour, move your legs and flex your feet to improve blood flow to the calves, wear loose and comfortable clothing and drink plenty of water.