badamz, there are others on here who can better tell you what happens if you don't get treated, but I know with me, I was extremely ill, lost tons of weight and was almost hospitalized and tube fed. Others end up having major surgeries. So, it is extremely important to get treated.
You can absolutely get misdiagnosed. It took 8 years for me to get a proper diagnosis and now, 5 years later, my doctor is questioning whether or not it was a correct diagnosis. Many people first get diagnosed with IBS, which is kind of a catch-all phrase that the drs use until they really figure it out, at least in my experience. I was diagnosed with IBS, my gallbladder was removed, I had surgeries for endometriosis, thinking that was the problem, etc., only to receive the Crohn's diagnosis later. It can take many years and many tests to get properly diagnosed, unless you get the right test and the right doctor at the right time.
I hope they find out that yours is not Crohn's, as it would be much better to just have IBS. But, I also know how great it is to get a diagnosis after suffering for a long time, even if that diagnosis is something like Crohn's.