Weak legs

Mary
Hello ladies! I am 32 weeks and two days with our twin boys, and for the last few weeks I have been dealing with severe weak and sore legs. Whether I've been sitting down for five minutes or sleeping for two hours, every time I stand up I feel like my right knee is going to give out and unless I put all my pressure on my left leg I can't even stand. And I'm limping in addition to the waddling LOL to get anywhere. Before I go anywhere I have to stand for at least a couple minutes to get my bearings. Is anybody else going through this?