I Had Unprotected Sex Yesterday With My Boyfriend... I Am

I had unprotected sex yesterday with my boyfriend... i am jz 17.... i cant even efford 2 consult a doctor nor buy a contraceptive pill... am not actually sure that his sperms went inside me but before some thing worst could happen...i would like 2 take some measures 2 avoid unwanted pregnancy...plz suggest me something ... if some thing wrong goes am sure my parents would kill me...plz suggest me an effective method ..