What Causes Delay In Periods,burning Sensation In Chest And Vomiting?

I had a reg cycle jan 19-24 6 days according to cycle calculator I ovulation 28& so on. I was sexually active on the 28, however I bled for 6 additional days after that..my cycle was supposed to come this month on the 16 as well as next month.. I ve been having heart burn soreness in my breast n I ve threw up yellow nasty tasting stuff twice am I pregnant