I have worn glasses for a lot of years. The first pair of bifocals I got did to me what you are experiencing. I could not wear them (falling, tripping,etc.). After several trips back to dr they discovered that the line on one one different than the other. When they had that lens redone everything was fine and I had on trouble. Many years ago my husband got glasses that felt really strange. He had to teach a class that first evening after picking them up. As a joke heput them on upside down and guess what -- they worked fine. Dr said he had never had a pair of glasses with the lenses reversed.