From everything I have read, Tamoxifen is for women who are premenopausal, and Anastrazole is for post-menopausal.

Oh I’ve never heard of both being given. If I had to chose I would definitely opt for Anastrozol. I would definitely talk with your Oncologist about the side effects of both drugs. It’s really important you talk with them. There are side effects but each person is different and you may not experience the effects like another person. The Anastrozol is causing me terrible fatigue and aching joints and muscles but I’d rather put up with that than risk the cancer returning. If I take pain relief then I can cope comfortably but I don’t like taking pain killers often. I still get the occasional hot sweats. Most importantly keep a strong, positive mind. Best of luck.

I just saw this:
Taking tamoxifen and anastrozole together was no better than taking tamoxifen alone. So this part of the trial was stopped. The women who had been taking both went on to take one or the other.

I know what you mean, I too fell like I’ve aged so much. I’m on tamoxifen now for 2 years and it hasn’t gotten any better. Most days I have joint pain and tiredness, but everyone treats me as if nothing ever happened. They don’t realize that this is my life now. The weight gain has been horrible even though I’ve been cutting back on my daily portions. Exercise has been harder because of the weather and I’m always on the go. But I will give it another 3 years then I’m done. I’m happy that I’m still alive!

My occupational therapist said to keep moving and the joint pain will diminish after a few weeks. I started anastrozole 15 days ago. I feel a little of the joint pain. I feel the fatigue but I think it's just part of the recovery. I try to stay busy moving.... also exercise and yoga.
I don't believe you should be taking both tamoxifen and anastrozole from what I have read. My oncologist gave me a bunch of stuff to read so I could make the decision, one or the other.. I chose the anastrozole. So far so good 👍
Good luck 🙏❤️