I've just done a CT scan too. In my case a Virtual Colonoscopy. There were no abnormalities. Like you, I find it hard to believe that I can feel so ill sometimes and yet have tested clear. I thought with my constipation and thin BM's I must have an obstruction. Especially around my ileo-caecal valve. It's good news but it's also bad news because it is so inconclusive.
Are you still taking Oxypowder ? You had some success with it?
Oxy and Chinese medicine are the only things saving me at the moment. But I am not really happy taking Oxy all the time. I would like to find a different Chinese doctor. Mine was very busy prescribing too many different things. I started to feel like a human guinea pig. I have reduced the medication right down to the minimum and just take a "tonic" called BU ZHONG YI QI WAN. This is for digestive issues. (I can't say this medication is suitable for everyone, you should have a qualified TCM doctor evaluate you and your body type. They should take blood pressure and pulse etc)
It comes in tiny pills and you take 8 x 3 a day. I take 2 x 3 a day and it gives me a real boost. But I am small and slim and according to the doctor react very strongly to Chinese medicine. Brain fog goes and depression whenever I take it ( I stopped during the summer and started again in autumn). What I like about Chinese medicine is that you don't get "die-off" reactions.