I know i should take one....but i just cant bring myself to do it

i am now 8 days late. I am frustrated because i just got my fist pack of birth control for my next cycle (the one i should have started and finished) and im going to be super upset if i got pregnant right before starting birth control.
i just feel like it should be near to impossible wearing a condom, pulling out, and checking every time but i still havent gotten my period, and i am never late.
i havent had any pregnancy symptoms other than my missed or late period but i my breasts are feeling heavy like usual before my period. i am just so frustrated