Hello and welcome, fellow Wisconsinite! First of all, whatever you're feeling, it's okay to feel those emotions. You've just been told that you have a lifelong, incurable illness. There's definitely a grieving process that goes along with that. It's totally valid to grieve the loss of the life you thought you'd have. It's okay to be angry, sad, terrified, frustrated, depressed - whatever you're feeling, it's okay and it's normal to have some extreme emotions when you're facing something like this. And we're always here if you need to vent or get support or just to know that someone else has been through it too.
And besides those negative emotions, it's also okay to feel positive emotions. There are a lot of good treatments which can get the illness into remission and get you feeling pretty much normal again.
And they're coming out with new treatments all the time - if you'd like to feel hopeful, have a read about what they're doing with stem cells, with the MAP vaccine, the SSI vaccine, fecal microbiota transplants, and so on. There may well be a cure not too far off in the future. So just remember, although there isn't a cure now, that doesn't mean there won't be a cure. And in the meantime, there are many treatment options to get you feeling much better.
As for your career, I can't really answer to that. Honestly, I have heard that being a chef is very stressful, and stress tends to make our symptoms worse. You might need to take more breaks to rest or use the bathroom more often. I know though that just like with medical treatments, there are also some innovative things going on in the culinary world. I have a friend who is a chef, and he's always spitballing ideas about starting a food truck, or an underground restaurant in his home, or a pop-up restaurant, things of that nature. He makes it all sound very exciting. So, if you find that your health is preventing you from being a chef in the traditional sense, you might want to look into other options like that if possible.