Hi. So, I'll try to answer your question but please know, it's hard to say from this vantage point. A gazillion little things can cause us to have a couple of days of discomfort. Most things easily resolve but if they do not, it's time to tell your mom/dad and see what they think. They can help you best as they are there with you and also will have access to providing you with actual care.
If it were upper right, I'd wonder about gallbladder but it is lower right it sounds like. Lower right can be associated with the appendix. Also, it can be associated, most definitely, with your IBS. It is very common to have this type of pain with IBS.
I'd talk to your mom about this pain if it continues (and that you are also sure it is not menstrual cramps).