@JacquiP
Sorry to read you are having such a hard time, physically and emotionally with tamoxifen. If it was me I would consider an appointment with the Oncologist to ask what are your alternatives as tamoxifen is not agreeing with you at all. Is it possible that it is at odds with your other meds?
You could ask if you could have a break from Tamoxifen.
If nothing else it will give you a clear indication of what your % is for taking or not taking.
Take care and best wishes
There's no right or wrong answer it is what is best for you
BTW The BCNA website is a great resource for understanding and formulating questions. There's a multitude of booklets - have you been given the Hormone Therapy booklet?
https://www.bcna.org.au/resources/booklets-and-fact-sheets/#hormonetherapy