You should see a GI doctor as you planned. The dark color stool is most likely coming from the constipation (the longer you don't go, the darker it is). Also, try to stay away from any citrus foods, tomatoes, spicy food, and things like that because they give you horrible acid. You might have IBS (Irritable Bowel Syndrome) and gastritis. Be very firm with the doctor, and if it does not get better, do not just let him/her brush it off. In my case, they brushed things off for so long, that now I am faced with partial or whole colon removal, among other things (and I am only 22!). So, do your own research before you go in, and ask lots of questions. I mean, don't be paranoid about it (I know that sometimes it can be very hard); just be informed. It is better to prevent things before they happen. Ask him about Protonix for the acid, and Miralax for constipation (and if Miralax does not work, you should try Zelnorm; it is generally really good), and some nausea medicine. Some of the tests that the doctor might do are CT (not painful), endoscopy (they put a little camera in and see your upper GI track; little uncomfortable after you wake up but not bad at all; they put you to sleep); colonoscopy (not painful), barium x-ray (just uncomfortable).... They probably will start you off with some meds and see how well you do. I wish you well. I hope you feel better. Let me know if you have any questions because I have done all of these tests and many more, and I have all and more symptoms like this. Take care. :-)