I had unprotected sex with my partner 7 weeks ago, I now have the following symptoms:-

Sore breasts for 4 weeks; tiredness; swollen and sometimes itchy belly; spots; backache; pelvic cramps and I constantly want to eat! I did a pregnancy test about 3 weeks ago and it came back negative but is there a chance I could still be pregnant? Something inside me feels different but I am scared to do a test in case it is negative. I really want a baby. Thanks for your advice.