Can I be pregnant?

I been on birth control for a month and I did missed two of my pills but I made them up next morning. On January 31 was my last day on my period and February 2 I had unprotected sex. Lately I been feeling very nauseous, cramping, gassy and my breast hurt and been looking bigger. Is there a chance that I can be pregnant? And to have pregnancy symptoms this early? I took a pregnancy test and it came out negative but is it to early ?

Thank you !