I agree, I would see a doctor if you haven't already and are not feeling better. Could still be the flu, but then again, it could be something else. It is always a good idea to have blood work done when things like this do not get better or get worse.
I think you should see a doctor cause what you are experiencing isnt normal. you might be having a flu but not all the time, chilling, having a high temperature and getting WEAK doesnt always mean FLU. maybe its more serious. and you r will never know maybe an hour after, your temperature will get higher.
Hope you get well soon..