morning, yes, delayed periods and then longer ones and sometimes shorter.. It's the hormones fluctuating...While I don't have Fibromyalgia, I realize now that many symptoms of perimenopause can mimic it, such as tiredness, fatigue, aching body... etc... You won't know for sure, although you can kinda guess if you are perimenoupausal unless you get a hormone test. Additionally, it's true that STRESS will throw your body, but so does the dropping of Estrogen (if you are perimenopausal) and that's because Estrogen is what controls our cortisol levels (the stress hormone) and as the Estrogen drops, the cortisol, not being as controlled can run amuck in our bodies and make whatever stress we are under (like holidays, school) much worse.. Additionally, you can still have a period WITHOUT an egg release, those are anovulatory cycles and as you age, you will have more and more of those. Hence, without the ovulation and thereafter, without the increase in progesterone, you can become as they say, estrogen dominant, in which case, or as in my case, I began to have fibroids. Moreover, with Estrogen dominance, again, it can mimic Firbromyalgia, which women are often diagnosed as having, when in fact, they don't have that, it's the hormones playing tricks on us (that isn't to say you don't have it) but rather to say that it can make fibromyalgia worse or at least seem worse. (check out Estrogen dominance in the body) lots of info on the net..
Once you get some blood work done, then you can know better where you stand, and with that, begin to educate yourself more about hormones. It's been my experience, that most doctors try and medicate, rather than educate.. much of what I learned about my body and hormones has been through my own research. I went this route because doctors weren't helpful. They's suggest surgery for the fibroids and or HRPT... I like to thoroughly understand my body before taking any medication.. Many doctors will only spend 15 minutes with you and that's it.. However, thankfully there are many groups/literature out there that explain hormones.. once you get your results, I would do research from there..
whatever you do, good luck !!