Hormone meds for breast cancer. Has anyone taken Letrozole? I'm worried about the side effects

I have had a mastectomy  done chemo and am almost finished radiotherapy. My oncologist has recommended taking Letrozole hormone treatment. I have been reading up on it and am worried about the side effects. Has anyone been on this drug and if so how do you feel. Im considering not taking it due to the side effects. If I decided not to take it would it be a big problem. Help!!