I've Been Having Sex For 3 Weeks And Two Days

I've been having sex for 3 weeks and two days every two days. I have a 22 day cycle normally I bleed pretty good for rour days and sometimes go through pads this month I started on the 15 normal flow its now the seventeenth and I'm just spotting. My nipples.are getting very very dark the first thing I realized. What's the chances of being pregnant. Also no protection and got off inside every time