PLEASE HELP ME

so I went to the doctors and got the pill and I told my mum it was for period pain when I actually wanted it for contraceptive reasons.. She has just confronted me and she saw right through me and said that if me and my boyfriend do have sex (which we have) in the house (which we have!) then I'm not allowed to see him again. WHAT DO I DO SHES GOING TO FIND OUT?!