Suggest Remedy For Pain In The Legs Upon Standing Post Burn Injury

I got burnt on the back of my legs and every time I get up out of bed or off the floor all the blood rushes down my leg and really really hurts. It takes me about 5 to 10minutes to get out of bed after the pain has settled. Is there anything I can do to stop it from hurting so much. Also I'm pregnant so im getting up to go to the toilet about 2-3 times at night as well.