Was On Cilatopram. My MD Stopped It. I Have Chronic

Was on cilatopram. My MD stopped it. I have chronic pain from arthritis ,fibromyalgia ,piriformis syndrome I am 61 yrs old. Since being off it for over month I now am sad. Have no energy. Want to sleep all the time. I have no suicidal ideations. I am a registered nurse I was on 20 mg daily I am going to put myself back on it ...the reason was because I am also on tamoxifen and per the pharmacist. As long as I did not take the 2 together and separated by at least 12 hours I would be fine. My doctors just stopped it cold turkey...what dosage should I start back on 10mg...?.?