Period or ?????

So last sunday 3/18/18 me and my boyfriend where about to have sex when !!! I start bleeding (let me mind u i still had not got my period my expected period was the following day) after the embarrassing attempt to having to have sex we came home to clean up snd my bleeding stops ? I yet to have bleed again ive tooken 2 pregnancy test this week and all are negative am i testing to early ??? Has this ever happened to any of u