it sure sounds like you are becoming menopausal. one test that would probably help would be to do a blood test to measure your estrogen level (estradiol) and a hormone called fsh (follicle stimulating hormone) -- made by the pituitary and as the ovaries stop working the pituitary gets working harder to try to stimulate them -- and the fsh goes up. if you are having bothersome symptoms estrogen would most likely help -- and presuming you are basically in good medical health otherwise your health-care provider could prescribe it to you. another possibility as you mentioned that you were dealing with significant depression would be an ssri type antidepressant -- it might well help with your mood and should also help some with hot flashes.
i had a partial hysterectomy in my ‘40's. at 51 i have hot flashes mood changes and depression. is this is menopause?