Whilst talking to my GP on other matters i happened to mention i am tired all the time. She organised blood tests which confirmed my body low in vitamin B12. The symptoms are fatigue, anemia and if left untreated, possible organ damage. Because my food passes through my system so quickly my body can't absorb all the necessary nutrients. I've been put on a course of Hydroxocobalamin injections with regular boosters in the future.
So, if anyone is suffering the same problem a simple blood test could provide a solution.