Could this be something to worry about?

For awhile now I have had leg weakness and pain. Two years ago I had a Doppler done where they indicated partial blockages but said it was nothing to worry about. If I try to walk around the block-the pain starts behind my knees and quickly moves up where I feel like I have to force my legs to move and my butt cheeks will go numb or go to sleep. I've dropped some weight with no changes to my diet. I'm 50, 5'7", and 116 lbs. I have no insurance to get multiple tests done. Dad's side has several different cancers (don't know a lot), he died of some form of bone cancer. Mom's side is diabetes and heart disease. Should I be worried? Any ideas on which way to steer me?