First of all, calm down. :) These FSH tests are not necessarily that accurate. There are lots of women who have high FSH levels and are still menstruating regularily. Conversely, there are lots of women who have low FSH levels and should be having periods, having none. FSH levels are "guides only" and should be repeated at differing stages of your cycles rather than based on one test level.
Secondly, while your FSH levels seem to be saying that you are "far from menopause".....let's get real about this! LOL You're 52 years old!! How far could you possibly be from it?! LOL The average age is between 50 and 55. You're already noticing some changes in your cycles and certainly these long, drawn out periods are certainly charactertistic of perimenopausal change type periods. After these types of periods, usually come the "was that a period?" type periods. Then, the...."Whoa....where'd my period go? Haven't seen it for a couple of months???"
Based on this one period and the one FSH test levels, I'd not be concerned at this point in time. You're certainly at the age where this is likely to happen and I certainly don't believe that you're that "far away" from menopause. You're already in perimenopause. It could be that you've got another year of regularity or less and will soon start skipping periods.
The only thing that I guess you might want to consider it making sure that your iron levels are kept up by eating iron rich foods or taking a multivitamin with iron in it as a supplementation when heavier periods hit. Trust me when I say that I had periods that I thought I was dying with! LOL Many of us in here can tell you stories of those types of periods as most of us have had at least one, if not many of them! LOL By the way, one of the side effects of these hormonal changes is weight gain and one of the side effects of weight gain is a storage of extra estrogen in the fat cells. Progesterone levels fall and that allows the extra estrogen to cause us to be estrogen dominant. Estrogen dominance can also cause higher cholesterol levels by the way. :)
My suggestion....let this period go for a few more days and see if it slows down. If it doesn't or it gets heavier and you're feeling "unwell" with it, give your doc a call. He/she may just want to check your estrogen levels and progesterone level to see if you may need some progesterone as the excess estrogen/lowered progesterone *can* cause a build-up of the uterine lining and the heavier and prolonged periods. And, because of your age, they may want to do a transvaginal ultrasound to check for endometrial fibroids which feed off of excess estrogen and grow larger until our bodies naturally decline in estrogen as well.
It's all in what makes YOU feel more at ease. If you are ill at ease about this and want more explanation from a doctor to help relax about it....give your doc a call/make an appointment. However, I really think that based on one period....you needn't worry at this point in time. And, I certainly don't think that you're that "far away" from menopause! :) You may have another year or so, but I'd not think that it's that far away. :)
Let us know how you are doing. Update us!
One last note here....Menopause is having gone 12 months without a period or the cessation forever of all menstrual bleeding. It does not take into account the 8 to 10 years prior to that "moment in time" (the 12 month period free point) in which we are going through all of the changes called, Perimenopause. So, for your doc to say that you're "far away" from it is a bit of a joke because you're already going through the prep stages for menopause! It's those stages that create the most problem for most of us. :)