pregnancy?

okay so i had sex last saturday and took a Take Action pill on that following sunday. i got my period tuesday but it’s been pretty light, i’m really small & 103 lbs. i’ve heard the heavier you are the less affective they are, and since i’m small i’m thinking i’ll be okay but i just want more opinions. let me know & if you’ve taken Take Action as opposed to Plan B tell me how it went!