Leanne, don't starve yourself to stay on the plan. You can always go back to it after you've been, and this time take pysellium husks from the start to prevent this problem. But please eat.
Love, I'd call the doctor or nhs direct if it's been this long. I would get terrible constipation on the Cambridge diet and only drinking about a gallon of lactulose plus taking epic doses of sennakot moved it. I couldn't do a diet where I had to keep that up.