Welcome NuNusmom - I am so sorry to hear about your son. I know this is a very stressful time for your family, but try not to be too hard on yourself. It sounds like you have been trying to get to the bottom of your son's tummy troubles for some time now and for many people here, it has taken years and years for a diagnosis. As a mother with Crohn's and a large family, I know how hard it is for me to deal with stomach aches and not think, "Oh no, it's a stomache ache, it must be Crohn's!" Of course, it's in the back of my mind and my husband is always telling me to relax. How were you to know that it was more serious when doctors etc. were all telling you it was anxiety?
You are blessed to have a diagnosis, and now you can educate yourself and work with the doctors to get your son back to better health. This is a great site for information and support. BTW, I have a friend whose son was also diagnosed around 11. After finding a treatment that worked, which did take some time, he is now a strong, healthy, energetic 15 year-old who has grown by leaps and bounds. I pray your son will start feeling better soon.
It is very, very common for Crohn's patients to have delayed diagnosis. This is a disease that mimics a lot of other conditions, like irritable bowel syndrome and stress-related problems. I imagine if you took a poll of all the people who post here, you would find an average delay from onset of symptoms to final correct diagnosis of from two to five years, with some going a decade or more.
You "make it up" to him by educating yourself about Crohn's and suporting him on matters of medication and diet, so that he can live as well as possible with this disease. You also recognize that it is NOT fatal and need not dramatically impact his life long term. Frankly, given the option, I'd rather have had a diagnosis of Crohn's at age 11 than, say, diabetes or cystic fibrosis or juvenile arthritis. I know ti may not seem that way right now, but there worse things to have.