According to the symptoms you report (breast tenderness, water retention, weight gain), it seems that you might be experiencing the typical signs (in certain women) of taking estrogens medications. Although the exact reason for the hysterectomy was not provided, still the normal findings of a PAP smear and mammogram provides the right information for your gynecologist to prescribe an adequate hormone-replacement therapy for the menopausal symptoms.

However, changing the treatment on your own might be highly inadvisable, since this could lead to a drastic hormonal imbalance in the organism. You might want to discuss the change of HRT (hormone-replacement therapy), change of the dosage, or simply switch to another HRT combination only with your gynecologist who is following and controlling your condition.