I have been through lumpectomy, then chemo/immunology/proton radiation treatment twice for recurrent TNBC over the past three years. I was put on AI inhibitors a year ago after now testing ER+ on pathology from my mastectomy. I was put on Letrozole first and my mood got so low that I thought I was in danger of committing suicide. (I've never had issues before). I switched to Exemestane and the mood issues went away, however the joint issues are getting worse. I just made the decision with input from my PCP to try Exemestane every other day (against my Dana Farber Onco's wishes, based on Dr. De Censi research). If that doesn't help, I will try Tamoxifen. I am battling as much as I can, but I am 74 and quality of life matters too. I am very active and social and I told my PCP, when I first got chemo, I was 70 and felt 50. When I was finished with chemo, I felt like I was 60. Now that I'm taking AI Inhibitors, I feel like 90. Good luck and I hope you can keep trying! The AI Inhibitors seem to hit everyone differently, so give them a try and don't be afraid to switch!