Hi For The Past Week I've Been Feeling Upset, Been

Hi for the past week I've been feeling upset, been burping a lot, have no appetite, couple of stomach pains to the left side of my stomach. It all began after I vomited frot and then hello like the yolk of an egg after that I have not vomit since but feel the symptoms. Should I be seek medical assistance or is it just gas as some friends are telling me.