Did they take biopsies during your colonoscopy? That should have been able to pin point if you have crohns. I know most doctors will not even consider crohns unless you have the hallmark diarrhea( which is obviously wrong since you can have it and not have the diarrhea according to a lot of people who have crohns and do not have the diarrhea.)
I am not diagnosed but have been having severe pains for 2 years now. I know what you mean about the Humira and those biologic meds. I myself would be sacred to take them too as they to have bad side effects. The question is, what all have you tried? Maybe you can ask your GI doc if there are any other options or meds that you can try first before going that route? Have you tried any of the diets yet( SCD diet, Paleo diet)?
If you are unsure never hesitate to ask your doctor and even go as far as getting a second opinion if need be. One thing I have learned with being chronically ill for the last 10 years is that you cannot trust doctors are always correct. For me, I have had more doctors be incorrect when it comes to my health unfortunately. If you are not comfortable, seek out a second opinion at least to ease you mind and help you make the decision on what to do.
Hope you get some answers and feel better soon....