Please someone read this !

Please ladies help me with your thoughts & advice....

What are the chances of me becoming pregnant If last night my bf finished then went inside of me again and today he finished right inside of me without me being on any type of birth control... I’m 18 And this past period is late by 5 days so I’m not really ovulating per say but I took a pregnancy test on Tuesday and it was negative so I don’t think I’m already pregnant but what are the chances from this situation of becoming pregnant .... thanks ... xx