not being able to keep food in for long times

Hello.

I am having problems keeping my food in my stomach long enough so I can pass it out normally, instead, after I eat, I have to run to the toilet and it passes through me within 10 minutes and i am in really bad pain.
when i was 13, i was diagnosed with Gastroenteritis, had the course of medication, nothing got better or worse, at ages 15, saw a different doctor, and was diagnosed with IBS, it took me 14 months to get a doctors appointment as the NHS where i live is extremely shoddy. the symptoms went away, and i was fine, until about 17 months ago, when this begun. I am now 19, and this problem is not getting any better. I have rang up the doctors every day since the beginning of December to get an emergency appointment, but I am yet to get an appointment whatsoever.

for example
tonight, i have had a Roast Dinner. and no sooner had i finished, i began to get excruciating pains in my stomach and a pushing sensation on my anus, i have had to run to the toilet and spent 25 minutes on the toilet.
but when i eat, i have to be careful. because it's not just certain things that set me off, it changes all the time, i'm yet to find something that i can eat without going through this pain.
i have to do this nearly every day.

[patient915]

Welcome to the gastroenterology community!  I think you need a lot more testing done.  These would include an upper endoscopy, a colonoscopy, a CT scan of your abdomen, and a gastric emptying scan.  You should see a gastroenterologist about this to get tested.  In the mean time I would recommend eliminating all lactose from your diet.

[doubleaaaron]

First of all you wont poop out what you just ate that fast. what happens is you will push the food out that was there previously. Do you have greasy stools? Have you lost weight? there are many things that cause the symptoms you described.