I've been getting the chills too..I'm not really quite sure why they are happening. I can't tell if they are the cold chills either. It seems like when I'm having an anxiety/panic/derealization attack they happen the most. Sometimes they just happen randomly. I'm actually getting them right now as I write this.

Read online about some of the side effects that whatever medicine your taking causes. That could be it, or just to rule out any infection in the body (chills can mean infection), go to your doctor and have them do a blood and urine test.