Tamoxifen side effects

I took tamoxifen for five years and came off it a few months ago. Just before I finished my oncologist said to me that most of her patients feel like a fog has lifted once they come of it. So foggy brain must be very common on it. To be honest I did not find it a huge problem although I do feel a little more clear-headed since going of it. One thing I think helped me was exercise. I always felt, while on tamoxifen and since finishing it also, that I feel more mentally focused, more sharp and alert after a good vigorous workout that gets the heart pumping. I usually run but I think a brisk walk does the trick too.