HELP!!!!

I’m on the birth control patch. I have unprotected sex with my boyfriend quite frequently. I have been feeling very nauseous and have been getting terrible migraines for the past weeks and a half. Are those signs of pregnancy? Should I be worried? I don’t have money to buy a pregnancy test...I’m only 17 and I don’t want anyone to find out I’m even having sex. I know this is stupid but I’m scared