Recently had blood tests for diverticulitis, gp rang 3 times in panic saying hemoglobin low which means I must be bleeding internally, spent 2 weeks in utter panic thinking I had cancer, but saw consultant on Thursday who said convinced diverticular disease awaiting sigmoidoscopy. But during that check up asked about medication and when I told him I take omeprazole 40 And have done for about 8 years he immediately said B12 deficiency hence low hemoglobin and anemia, if you take this google it and you will see, he was really angry that I was not tested for this and will now be, why did my own gp not think of this and why was I not warned and regulary tested, instead of panicking me about internal bleeding even when I explained there is none, I do not pass blood from anywhere, periods stopped. So if you are feeling tired whilst on this get yourself checked as according to consultant dangerous if left.