<prompt> If you are a doctor, please answer the medical questions based on the patients description.my last period was 72112 it lasted 5 days my cycle is 21 days. my period has yet to come on. but i have been get sick after i eat, and today my belly button was hurting it feel like something is being pulled inside my stomach and i get a sharp pain in my belly button what could this be???  <response>: Hi, If your periods have not come yet, I suggest running pregnancy test to exclude a possible pregnancy. Furthermore, I also suggest to: - do abdominal ultrasound-do urinalysis- run vaginal swab testing to evaluate the abdominal and genital organs and to determine the right problems. I also advise to: - often eat and small portions-avoid citrusfattyfried foods-avoid alcoholcoffeeenergetic Chat Doctor. 