You need to make an appointment with your primary care doctor. Your doctor will need more details about your symptoms.
How old are you? And when did you first begin having any abdominal discomfort or bowel movement changes? If you are in your teens or twenties and the symptoms have been present for more than 6 months the most likely diagnosis is irritable bowel syndrome (IBS). But there are multiple other possibilities.
To rule out those possibilities, your doctor will ask additional questions.
You mentioned that you had no weight loss. That is reassuring. Your doctor will also want to know if you have had any fever, traveled outside the United States, and/or had specific areas of pain in your abdomen or elsewhere. If you answer yes to any of these questions, your doctor will consider the possibility of an infection. This is especially true if the symptoms began just recently.
Do the symptoms wake you up at night? In general, people with IBS dont wake up during sleep because of symptoms. Other conditions, such as ulcerative colitis and Crohns disease, can cause symptoms at night as well as daytime.
Have you noticed any blood in your stool? If yes, then you likely need further testing before calling the problem IBS.