Could I be pregnant or other female disorder? I am 37 years old, I just had my GYN exam the doctor told me I?

was not pregnant, but I have not had my period in 2 months. I did have an abnormal pap smear but the HPV was negative. I am with the same person for 14 years. I have a son that is 16. I do want to have another child. My fiance has no children, about 12 years ago I did get pregnant by him but I had a lot of problems and 7weeks I did get an abortion. I do have occasional lower back pain. Does anyone have these familiar symptoms?