First off then, if I was back in your situation again I would try and follow a low Fodmap diet....
Write down the foods you eat each day and when you manage a poo.
You need this if you can get a refferal to a gastroenterologist anyway.
I already have a diagnosis of SCT but I have been back to my GP today and because I have moved house 4 months ago I had previously asked this new GP twice to be referred back to a gastro person. Today, armed with a calendar with everything listed on it-poo, dulcolax, food, morphine, diazepam doses etc... And photos of poo on my camera. I have got an immediate referral now...
We explained this morning that nobody else has to do this and asked if he thought this was normal, nice, living when you have to write down every food, every poo just to try and live a normal life....
I do so empathise... I would suggest looking and trying a low fodmap diet for a few weeks, eat small regular amounts of food. Write everything down...then go back to GP.
It is important to look at the foods you eat. Ie people with IBS, slow colonic, gastroparesis should try to avoid onion in anything.. Its hard to do... Same with garlic. I love those two foods myself but have to check everything for them.. Having to make own gravy stock, avoiding lactose yogurts etc...
Stomach bloating is awful too. I also have photos of this to show my gastro chap when I get re referred again...
Get everything logged (ha!!) and then go back to GP and ask for a referral if nothing improves...