I agree with Cadigurl... try to rest and eat what you can until this passes. We never do the flu shot at my house and none of us have ever had the flu.
I think it could make you sick there are so many additives that they put in the flu shot its not just the virus your body is probably rejecting the chemicals and additives. The flu shot is such a scam there are thousands of flu viruses so getting one type will not save you from the other 999 that are all around. Best thing is to incorparate organic cocunut oil into your daily diet and load up on organic fruits and veggies stay away from convetional grown they are covered in pesticides. This will strengthen your immune system and your body will fight any virus you may come in contact with.
The flu shot can not make you sick so this is most likely psychosomatic, or a flu that you were developing before you got the needle.