Hi, I've Had Major Surgery For Bowel Cancer About 6

Hi, I've had major surgery for bowel cancer about 6 months ago, 2 operations in fact.. my diet is we v merely limited as I can't tolerate fibre in my diet any more. I've recently been feeling unwell with lethargy, headaches,bloated tummy, nausea and now a coated sore tongue. Should I be worried? Didn't realise you had to pay, I'll leave it for now thanks