Inflammation of the colon may cause pain in your lower right abdomen. The pain of appendicitis may also spread to the lower right abdomen. I'm going to also include a link about what to look for on appendix. Do read it over, just so you are familiar with it. Appendicitis
Although as long as you take your pill each day, chances of being pregnant is low, but I wouldn't rule it out yet unless you do so via a blood test from your doctor, which is much more accurate than a home test.
It may just be intestinal infection which can cause the symptoms you have as well. But either way, I would try to see your doctor tomorrow, to rule out any pregnancy (which could be ectopic as well) or any intestinal/colon infection, as this will require a course of antibiotics.
Another thing that can also cause pain in the region you state is ovarian cyst, but for now I would rule that out. But your symptoms do warrant a trip.
Best of luck Hun, Hope this helps, If you need anything else please feel free to ask. If you found this helpful don't forget to click the *ACCEPT* button and leave *POSITIVE* feedback.