Hello Welcom to HCM
Thanks for the query.
Pain in Rt Lower abdomen starting from navel and moving downwards with loss of appetite is most commonly due to appendicitis
. Though there may be other causes like Mesentic adenitis
, ureteric colic diverticulitis
I suggest you to get your blood examination and sonography
report done soon which will help in early diagnosis of your problem.
And if you are having severe pain
and not feeling really well i advise you to go to emergency to a hospital and get yourself checked and if necessary admission so that treatment can be started early to avoid any complications.
Wish you good health and get well soon