Yes, believe your doctor. Chemo can cause a lot of strange reactions besides losing one's hair. Premature menopause is only one of the symptoms. The sweats you had could be related to menopausal hormone problems...whew, I had a hell of a time myself. Terrible mood swings that had my doc wondering if I was bipolar and temperature changes--one moment freezing and the next moment sweating to death. And then being all sweaty, I'd get a chill and freeze all over again. A really nasty cycle that lasted for almost a year until the doc started me on hormones. It took 18 months to find the right therapeutic level but have had no problems since then and it's been 8 years.