I've Been On Estrogen(.3mg) Since My Total Hysterectomy At Age

I've been on estrogen(.3mg) since my total hysterectomy at age 47. I'm 68 and stopped taking estrogen a month ago. As I'm experiencing hot flashes and sleep disturbances, I'm considering going back on estrogen. Would this be too risky? My nutrition is exemplary, I exercise almost daily, and take 25mg Losartan, 20mg Simvastatin, and 50 mcg Synthroid. I have never smoked and only drink an occasional glass of red wine.