I have just completed the 4 weeks of repair stage, following the recipe suggestions at the back of the cleverguts recipe book. I was feeling good, and my IBS symptoms have reduced however for the last week I have been waking up with symptoms similar to a hangover. I am dehydrated, and need to drink a few pints of water before my thirst is quenched. I also have really bad headaches and have some nausea. The headaches can last all day. Is this normal?