I'm cold and chilled all the time taking Noladex

I'm 52 years old and started taking 20 mg of Nolvadex daily starting 11-1-05, just as a preventive measure. For the last 4 or 5 weeks, I'm chilled to the bone almost all the time; it doesn't matter how warm I dress and how many layers, it's like the cold is coming from deep inside. I'm starting menopause; my periods were regular (but heavy) up until about 6 months ago. I always got the chills for 3 or 4 days prior to my period, but now I'm cold ALL the time. My last period began on 1-8-06 and was extremely heavy and lasted 7 or 8 days. I started flowing again on 1-25-06--again it's been extremely heavy. I just can't seem to get warm and stay warm. Does this sound like a side effect from this medication? I would appreciate any information you can provide. Thank you.