What Causes Severe Chills And Tremors In The Body?

My name is Helen...I am 62 years of age... I had severe chills - without fever last night....took a couple of hrs. to slow the shivers enough to get to sleep...wakened this am to a feeling that an earthquake was occurring inside my body....totally quivering...entire body. this has happened before but not quite to this extreme...and not for 3-4 months...came on very suddenly....felt like I was totally frozen.......and could not warm up despite being snuggled by my husband and having more than usual amt . of blankets. I could feel the warmth of husband...the warmth of blankets externally....but no warmth inside at all. What would cause this?