Karen,
If the FSH was high, that might reflect a decrease in your available egg supply this month. When the ovaries don't respond right away, the brain responds by making more FSH than usual. Hopefully, that was a transient rise that will go back down. When a woman is in menopause (i.e. no eggs in the recruitable pool) then the FSH levels get very high. If you haven't checked, it may be good to measure your AMH level and to do an antral follicle count.
If you are on estrogen therapy, then it can be hard to interpret the cervical mucous signs because one of the effects of estrogen is to increase cervical mucous. Interestingly, no one can look tell if a molecule is an estrogen by looking at its structure. We define estrogens as medications/molecules that have estrogenic effects, i.e. they thicken the lining of the uterus, increase cervical mucous, etc. You may not know if the changes are due to your own bodies estrogen or the estrogen that you are taking. It is good that you are in the hands of an RE to help you figure some of this out. I can get complicated and they have a lot more information than you are able to share with me. Sorry I couldn't be more help. Good luck!