Hi, my boyfriend and I had sex on the 17th during the late afternoon, he was unsure if he came in me as there isnt any protective measures taken, so I headed to get a morning after pill on the 18th and I took it during the early afternoon, but after 4 days I am having a headache, nausea, and cramps, may I know the chances of me getting pregnant and how do I know if the prostinor worked?