I Am So Confused... I Have A 5 Year Old

I am so confused... I have a 5 year old boy and I found I was pregnant with him when I lit a cigarette several times and constantly became sick as well as having very sore breasts. I have been trying for another child for 2 years I have not been on any birth control. My menstrual cycle comes once a month but never at the same time, and they usually last about 3-4 days. It seemed that I was spotting 2 weeks ago but only lasted half a day, I started my period 4 days ago and am just getting off of it but I have been extremely nauseated for 5 days straight and just yesterday any smell of smoke or lighting a cigarette is making me vomit.