Could Missing Periods Be Due To Pregnancy?

hey please help at the earliest...
my gf last period was on 4th april and she was supposed to have it again on 2nd may..but she didnt have it...and we had sex without condom on 2nd may afternoon....she didn't take the pill until 5th may evening....after having the pills we did have sex for three more times without condom and i did cum inside her.....does it mean she will get pregnant..coz she feels a bit sick in her stomach