Am 38 weeks pregnant and have been experiencing EXTREME swelling in my lower extremities only.?

I am 38 weeks pregnant and have been experiencing EXTREME swelling in my lower extremities only. My legs have gotten HUGE, full of water!! My doctor tells me its nothing to worry about, its not toxemia because my blood pressure is absolutely normal and urine test also, but I am in pain! Cannot even put pants on because Im so swollen and cannot bend my legs due to it, it feels as if I've been beaten in my legs and feet. I cannot walk much or stand at all for a period of time. I've been like this for about a month and have been on bedrest w/ my feet elevated, drinking gallons of water, but nothing seems to help. My worry is if I can develop a blood clot, now or even after my scheduled c-section next week. Doc says swelling will remain for a few days after delivery. Has anyone experienced such MAJOR swelling in the legs?