Strangest thing happened during Infusion

I had my infusion today. Nothing special, although I had a headache and was really tired today. Strangest thing happened about 45 minutes into it. I started getting the chills - the kind that run up/down your back and make you really shiver. I asked for a blanket (I turned it down at first because I was warm and didn't need it) and after a while it seemed to help. Then about 1-1/2 hours in, the chills came back for awhile. Went away and when I left I was fine. I have never experienced chills during my infusion. Normally, it generally takes quite a bit for me to get cold and it takes 5 minutes for me to get hot.

I know my blood pressure drops quite a bit during my infusion, but I'm not sure that this was the reason. Strange - I don't know what to think about it. Does this happen to anyone during infusions? Could it be because I was tired and had a headache? Appreciate any comments.

~S.

I have never had a remicade infusion, but I understand that chills, and other "allergic-type" reactions are quite common. 

El