Is estrogen the only thing that warrants Tamoxifen ? ?

[mts]

Hello Ladies and Gents-

So, I am ER positve less than 20% and PR neg.
Last year the onc said it was OK for me to get off the tamoxifen (I hated the way it made me feel). I had also posted on this board about this issue and the responses went both ways. Last month the onc suggested I get back on the Tamoxifen because it "does provide a benefit"... like 3% !
So if you have any ER positivity you get tamoxifen.... is it that simple ?
When I got off the tamoxifen I was almost menopausal - Which with my low ER% was enough reason not to take tamoxifen. But now my periods are back (have been for about 6 months). I figure he wants me back on Tamoxifen to get me back into menopause...
I got my Px and just don't have the guts to take it. Here I am 3 1/2 yrs out from Stage I, I know that status can change overnight, but yet the added benefit is so darn minimal that I have a hard time validating taking it.

My question is: Is the ER percentage the only thing that warrants Tamoxifen or are there other biologic/metabolic factors that could be factored in ? I know this may sound whimpy when so many other women are taking heavy duty stuff, but I realy want quality of life and the tamoxifen did not give that to me. I have read over and over on this site about vaginal atrophy and dryness loss of libido...etc. I also took the effexor to counteract the tamoxifen... the effexor made me feel like I was wearing an iron helmet all the time, and constant motion sickness (sitting on a noodle at the beach makes me barf). I know no one can make my mind up but me, but I would really like to read any comments or advise...

Maria