 [ Symptoms ] can you drink alcohol while you are on a zpac azithromycin [ Disease ] based on your history i would seek medical attention using plan b twice could cause irregular bleeding but highly unlikely to cause severe suprapubic pain since you are on the nuva ring you should always insert the birth control even after using plan b if you became pregnant of course your period would not come the following month but its best to stay on schedule with birth control if not you start to miss with your cycle which can cause scares best thing to do would be take a pregnancy test first then call your obgyn and have an appointment set up also plan b should only be used in emergency cases and is not safe to use every time a mishap comes along