Crohn’s disease, diverticulitis, infection in kidney, kidney stones, constipation, ovary involvement
in women, ectopic pregnancy
in women, mesentry (a thin tissue that carries the blood, nerves and lymphatics for the intestine) involvement, and an abscess in rectus abdominis muscle or psoas muscle can all cause lower right abdomen pain.
If you cannot consult your doctor until next week, maybe you can go to ER. The symptoms could be due to IBS but appendicitis needs to be ruled out.