hi Doctor , I m 18 and i feel like vomiting most of the time.even if i had just eaten a bit, i feel like throwing up. But i never throw up. then I ve checked all the pregnancy signs,Ive never missed a period. I had my period last month. I have irregular period just this year and I ve noticed that my period for the current month comes first week on the next month. my period usually comes between the 23rd and 28th but since 2 months ago, I ve been having my period between the 2nd and 5th in the next month. what s wrong with me? and I ve been having lower abdominal back pains.