I totally understand your anxiety and think we all feel that way to some extent after a loss of faith (because of breast cancer diagnosis) in our health. I know I get much more anxious about any health test these days. But as you say, you know logically that there is no reason to think that there will be anything wrong.
You know that you are feeling better on your treatment and lots of people have a good quality of life for many years after a mets diagnosis. So it is still important to look after the rest of your health. I would definitely go and have the Pap smear. Getting some support, like the other ladies have suggested, might be a great idea to help you feel ok about having this done. Whatever helps you feel better. Take care and let us know how you go. xxx