am i pregnant

hello Doctor.
I had a sex on last month's(sept) date 28 then i had period on 8 october which is 10 days before the date of my period.Then i did sex again on 23 october and i have not periods right now.Both time my male partner use condom.Now still I want to know that am I pragnant, and after how many time of sex will periods be stop? Because from yesterday(25 oct) i had womiting sensation.rest is no change in my body.I m getting affraid of being pregnant because i m not married yet.
I dont know anythig about all these.So please reply me as soon as possible.