Arimidex and Lexapro

Diagnosed with stage 1 DCIS left breast. Lumpectomy 4/17/26. 5 radiation treatments. Clear margins. .2 mm tumor size. Caught very early. 76 years old. Was told by medical oncologist that I must stop Lexapro (20 mg daily). I am a long term (20 years) user. I successfully weaned 2 months ago, but am really struggling. Do not know if my mood swings are from menopausal symptoms from Arimidex, or stopping Lexapro. Also having a lot of bone pain and joint pain. DEXA in February showed -.8 at hip, +1 at lumbar. Osteopenia. I am struggling. What do studies show about Lexapro affecting Arimidex effectiveness? Perhaps if I felt better mentally, I could better tolerate side effects. Ideas?