Could I be pregnant?

My last period was 3/9-3/13 and since then I haven't gotten my period. On 3/19 I had sex with a condom, then he took it off then continued for not even 10 seconds (he did not ejaculate at all). I had cramps and had a light "period" for 4 days about 2 weeks ago, but it was like my usual periods, it was happened before but I keep thinking it was something else. The light "period" was brown then dark red. If that wasn't my period id be on cycle day 36 and still nothing? I have also always been irregular. I have absolutely no symptoms for pregnancy and I'm very paranoid and scared! I'm only a teen so I'm really not ready for that! Any comments or suggestions would be a total stress reliever! Thanks!