What Causes Delay In Periods Inspite Of Taking Mensovit?

First time I had a sex with my boyfriend and I didn't take any tablet after a one week again I had sex but on that time I had taken birth control pill but now this is my second month and I didn't get my periods and now I am taking mensovit tablet also that too I didnt get my periods as I am 20 years old plz suggest me is I am pregnant