Hey Bella, how long have you been on the diet? If your body is trying to go into ketosis you can get bad headaches to start off with for the first 5 days or so then it should ease off. Mine didnt this time (they changed Cambridge from the last time I did it) so I changed to exante instead and was fine once in ketosis. If they dont go away, up water more or try a different thing or more calories? and check with Dr that all is well x