Sorry you haven't heard back from anyone yet. What did your doctor say? A drop in FSH often means ovaries aren't making eggs, pituitary gland isn't working properly, you are underweight, hypothalamus issues. Those are the normal culprits of a drop in FSH. Please give an update! Not ovulating due to age and whatnot could really be the case. https://medlineplus.gov/lab-tests/follicle-stimulating-hormone-fsh-levels-test/