I Have Chills With No Fever At Night, Even Though

I have chills with no fever at night, even though the room is warm and I have three blankets on my bed. I am awaiting lab results on my endometrium, as I have been bleeding heavily on and off - four times - in the past 7-8 weeks, for more than a week at a time. My body hasn't produced a fever in over 25 years, so I am worried as to what this could be...