What Causes Greenish Yellow Discharge And Delay In Periods?

I missed my period last month and my period still has not come for this month. I have cramps and slight pain in my lower abdomen during the day and night. Last month I had to take medication after going to the ER due to difficulty breathing and inflamation in air/lung tubes. I stopped taking one of the two medications requiered because I did not want to swallow two large pills anymore. A few weeks later I started cramping and feeling nauseous. I still feel like this and also feel dizzy at times. I have a greenish yellow discharge that looks a little like snot. I also feel tingling in my breast here and there and pain in between my breasts. Is it possible that I may be pregnant?