It is very difficult to answer this question without having a lot more information on what is going on. For example, what are the other symptoms you are experiencing - is it pain, nausea, vomiting, weight loss, blood in your bowel movements? In the absence of these data, it is hard to give a good answer. Therefore, I would suggest going to see your primary care doctor
as soon as possible to help you sort things out.
In the mean time, you can avoid any potentially damaging things to the gastrointestinal tract, such as alcohol, smoking, large amounts of caffeine, and drugs like ibuprofen and naprosyn.
Also, if you have any very concerning symptoms, such as blood in your bowel movements, dizziness
or fatigue, vomiting blood or unstoppable vomiting, or severe abdominal pain
then these would all be signs of a potential emergency and you should go to the emergency room rather than waiting to see your regular doctor.
If you are not having any of these concerning symptoms, then you should make a list of the symptoms you do have, including weight loss, association with foods and medicines, and other medical problems so that your meeting with your primary care doctor is as productive as possible.