As you guessed, all doctors, like other human beings, are different, but there ARE some standard things that they always do. Like you eluded to....they take a personal and medical "history" from the patient. Which basically is just asking you questions about why you came to see them, what your symptoms have been over the past, what your present symptoms are. A family history, etc.. Then most likely an exam. Not always a rectal exam. It all depends upon what you say your symptoms are, pain if you have some, and where it is located, etc....
I find they do a lot of discussing mostly with you on the first visit. After they do an exam on you, then depending upon their impression, they may order some tests for you. On some occasions they may feel confident enough just by your history and symptoms to actually presecribe medication on the spot.
I would definitely recommend that you do see a GI specialist, and please do not be too nervous or stressed.
A good hint, since you probably will not be able to help being a bit nervous, is well before your appointment, begin taking daily notes about your daily routines, eating habits, activities, pains, symptoms, etc... that way, when you arrive at the appointment, you will have your little notebook handy, and will be able to give the doctor a MUCH better picture of what is going on with you.
I have crohns disease and to this day, since I write in a daily journal, I bring it with me at every single visit. I still tend to sometimes forget to mention things, that even though they may SEEM insignificant to me, can, and HAVE proven to be significant to the doctor in pinpointing what is going on with me.
Good luck to you Staci, and please let us know how you are doing, and what you find out. Especially if you do see the GI specialist.