Diarrhea after taking antibiotics.

I have some ear pain, lower jaw pain with swelling since may. I have been prescribed amoxicillin in may for a week. I took it for a week. Went to ENT and he gave cefdinir for a week in June. I have taken that for 4 days. Extracted wisdom tooth in July and taken antibiotics amoxicillin for a week in July. I still have the same lower jaw pain. Dentist told me that I need a RCT. So, he put me on antibiotics amoxicillin now before root canal treatment. I took amoxicillin twice a day for past 2 days. Today I have stomach cramp, discomfort and passed loose stools 4 times. I am passing stools immediately after eating or drinking tea/coffee. It's loose liquid stools. I hear some grumbling noise in the stomach. Is this normal? Taking too much antibiotics in the past 3 months harmful to the stomach? I have taken liver test and kidney blood test last month and both were normal.