Okay So About A Month Ago I Had Unprotected Sex

Okay so about a month ago I had unprotected sex and lost my virginty. And my stomach is huge now. So far I haven't had my period this month but I did last month. So could I be pregnant? I done the baking soda thing and it said I was but I just had unprotected sex like an hour ago and I'm having bad pains in my waist line area it hurts to move it. Any way I could be pregnant?