PMS, fibromyalgia and irregular period

Im 27 years old and I have fibromyalgia. I daily suffer from lower back pain which gets much worse when I ovulate and 10 days before having my period.

The last 2 years I haven't had a regular period, sometimes its 30 days sometimes its 40. My normal was 28 days. I've also noticed that in some months I ovulate 2 times (is that actually normal?). I've done blood tests to check my hormone levels and my estrogen is a bit low (20). I asked my doctor but she said its not a problem according to my weight. I have very bad pms, its destroying all the effort I make to keep my fibro pain under control.

I had tried the pill (Yasmin) which caused severe nausea as a side effect. I couldn't eat anything. I stoped it after a month.

So... I've been seriously thinking if the progesterone cream could help me! Thank you!