Pregnant or not??

Hello every one, My last period was February 27 til March 5. This month of March I'm waiting for my period, but Im overthinking if I am a pregnant or not. I already got a pregnancy test but it shows Negative one line only. May partner and I used contraceptive condom always. Pero may one time na nag do kami wala siyang gamit but he didn't finish naman po kundi sa labas niya po inilabas I saw it with my 2 eyes. So help me po if Iam pregnant or not. Thankyouuu po!!