17 and pregnant???

Hi, im 17 i am almost a month late for my period and ive never missed one before or been late. my boyfriend and i had unprotected sex very often in october and still are. im unsure if im pregnant i have most of the symptoms, and just this last week started to feel a tightening in my back and hip area almost like a lot of pressure. my whole family has noticed and ive taken some at home test that come out negative. i dont really have the money for a blood test but most of my family said they couldnt get a positive urine test until almost 5 months. can some one help me plzzzzzz