I've been on mononessa for a while and I've been taking it pretty much on time regularly. I was supposed to start my period this past Monday and now it's Thursday. I had sex with my boyfriend last Saturday and I'm starting to become kind of panicked. I don't know how high the risks are or what. I also used to take a different pill and it caused me to stop having periods all together so I don't know if that is happening again. I don't really know if I should take a pregnancy test I feel like it's not possible to be pregnant since I'm so good about taking them but I don't know what to think.