got my period about 11 days late. I had unportected sex throughout me "fertile" period. I am a reg 28 day cycle. I was a mini pill user. I failed to use a backup method during the first week of use which happened to be ovulation week. I had btb for about a week. Had unprotected sex twice more after btb. Came of the pill instantly. I was on the pill fir less than a month. Well on day 12 I started getting killer lower back pains and later on I started spotting. Really light sort of brown like in color. The next day more redder but with a water like consistency but not heavy. No need to change the pad. (I am usually heavy the first few days. Today the bleeding is still not heavy with a pink brown like color to it, but red when I wipe.(Sorry) The thing that makes this different is there is no odor whatsoever. Could this be decidual bleeding. I did four hpt early on and they were all negative