Started the John Briffa advocated diet from 'escape the diet trap', recommended by a friend who lost a huge amount of weight over 8 months and feels great on it. I got on well, enjoyed the food, not hungry etc but then this morning I woke up so weak and shaky I had to lie down while DP brought me orange juice! He had to bring toddler to nursery as I felt too shaky to drive and just went to bed with the baby for the morning. What could be going wrong??