Hello there, welcome to the forum.
I am sorry to hear you are having difficulties. As someone said above, many of the tests for Crohns disease are similar to those for UC so hopefully there won't be too much you haven't come across before.
I understand it must be daunting to have been diagnosed with a condition for so long and then suddenly get told it may be something else, but this is a great forum and i'm sure you will get lots of support whatever the outcome.
With regards to treatment, this is also fairly similar, but some doctors are more aggressive in their approach to Crohns disease and therefore may prescribe a treatment like remicade earlier than they would with UC.
If you have any specific questions please don't be afraid to ask, there isn't much that we haven't seen or been through as a group so there's usually someone around that can relate to what you are going through and give a helping hand. At the very least we can be a hand to hold and a shoulder to lean on when times get tough. There is no question to big or small, there is no such thing as a silly question, and there is no need to be embarrassed with us, we are all in the same boat.