I started on Anastrazole and did fine for the first few months. Of course brain fog and a little achy but nothing I couldn’t deal with and of course the brain fog could have been from the chemo or radiation. By 9 months though, it had gotten to the point where I was looking for the guy with the knife, everyday stabbing pains somewhere - just moved around. So we went to exemestane. Again fine for about 3 months then weight gain (10# in a week with no changes to diet or exercise, had to do 24 hr liquid fast to stop it) followed by extreme fatigue. While not sleepy per we, I would nod off in the middle of things, a bit afraid to drive later in the day. He did tests to rule out other causes, all neg. Then the insomnia hit - barely able to get 3 hours a night which made the fatigue worse. Felt weak, unable to do much so stopped going out. Didn’t want people to have to stop and wait for me. Along with this was elevated bp, heart rate, difficulty using my hands/thumbs (not really trigger thumb, just swelling and pain, thought it was arthritis). At about 18 months onto this, Told me to stop for 4 weeks and I took 6 because I didn’t even feel human till 4weeks. By then, few afternoon naps, 6-7 hours sleep, normal bp, back to my mile+ walk daily without stopping every 2 minutes to catch my breath, stopped forgetting what I was going to do and the pain/swelling in hands went away. He wanted me to restart, won’t entertain lower dose like every other day. Within 2 weeks it all started to come back. BUT no pain. I’m now about 2 1/2 weeks into Letrozole and we’ll see. Hopefully the exemestane works for you. Everyone reacts differently to each one and we have to eliminate the effects of the medication (no estrogen effects) from actual side effects of the drugs themselves. My oncologist says he’s had some patients who don’t tolerate any but we have to give them a try.