Why should I HAVE to get used to new glasses?

I have worn glasses for over 20 years. I have always been near sighted. After having each of my children my vision actually improved to the point that I really barely have a prescription in my left eye and pretty much none in the right eye. I have had the same pair of glasses for 6 years because my prescription never changed. Last year I had to switch doctors because my old one didn't accept my new insurance. The new doctor was very friendly and thorough. But he was telling me that I had an astigmatism and I could never wear contact lenses (HELLO… I wore contacts for 15 years with zero problems! Only quit because of the cost.) and he said that I am not near sighted but am actually far sighted now! I guess he's correct since can see pretty well far away. And have the beginning of presbyopia (aging eyes). The only reason I even wear glasses now is because that left eye has that touch of prescription it and doesn't match the right eye and bothers me. Anyway, I broke down and bought new glasses finally. Wasn't cheap! Got them today and they are WRONG! The left eye feels wrong, is slightly blurry, and its giving me headaches. I told them this and they said "oh you have to get used to it. Give it a few days"? Why should I have to get used to it? If its the right prescription then it shouldn't take getting used to. A doc told me once if they don't feel right immediately (blurry, slanted floor, just feels off, etc.) then something is wrong. Any thoughts?

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