hi, me and my boyfriend had sex about a week ago.. under the influence & did not use a condom.. he didn t bust but just to be sure I took plan b within the 72 hour time frame .. because of the unprotected sex I think I got a uti which I also had 3 weeks ago because of having sex .. I took macrobid and it went away .. now that I have it again I m worried that the macrobid and plan b will interfere with one another & I want to refrain from telling my doctor that I did take plan b .. is plan b out of my system? and would a uti antibiotic interfere with it? do I need to tell my doctor?