Re: endometrial thickening
I am 50 and have fibroids but don't have endometrial thickening. As I undertand it, both these conditions are stimulated by estrogen and at perimenopause (around 45-50) progesterone goes down. Progesterone keeps estrogen in check, so if prog is less, there is more "estrogen dominance" and an overstimulation of uterine tissue in some women.
I think usually uterine thickening does not mean a serious condition, but i'm sure this is all upsetting. As you probably know, the D&C will thin the lining and they will check the cells to make sure all is well.
Re fibroids, there are alot of options other than hysterectomy these days. UAE (Uterine Artery Embolization) and a newer procedure called FUS (Focused Ultrasound). I had the UAE done in 2006 and was having some bladder issues, which have now resolved. You might want to visit the hysterectomy section on this site, as they discuss not only hyst but fibroids and other treatments for fibroids.