I was diagnosed with lactose intolerance at around 10 years old. I had similar experiences as what you have described. I would also see about IBS (Irritable Bowl Syndrome). My family has digestive issue that seem to run thru it, and many of us have experienced either of these conditions. To be sure it could be linked to dairy, have her not eat any for a week and see if it makes a difference. Also, it may be hormonal.
i would see a doctor about it. it could be something like celiac disease, and the other "triggers" just a coincidence in timing.
i would do a complete food journal for a while to look for more definite patterns. you may be surprised by what you find.