HELPP PERIOD CRISIS....?

okk so my mum found a pair of pants in my room that i had my period in and they must of like fell out went under something when i was putting them in the wash so anyway i didnt wanna be like a tramp and tell her i forgot to put them in the wash so i just told her i was on my period when i had my period about 3weeks or so ago, and she thinks im on it so she put it on her calander and i told her i started it on sunday(lie) and she is counting the days untill im next due so i dont leak again and no when to put on a pad but the fact is that im not on my period at all and she thinks i am and now i have to pretend to be on it and im prob getting my period soon and ill prob leak in my pjs cuz i dont no the day i had it and she will wonder? and prob think there something rong with me what to do?