May be pregnant on birth control

So nov.23 i had my iud (mirena) removed due to having 2 week periods that were heavy while on it... A few days later i had a 5 day period. On dec 2 i started a birth control pack and dec 4th my husband and i had sex he didnt finish but says its possible he could have let a little go... Fast forward and no period completely missed i messed up on the bc pack after that but nkt before it like in the middle of the pack i missed 3 days really 2 but wad on the 3rd day and missed the specific time and it was 10pm so i took the 2 previous pills and then the next day i took that days pill and the day before to fix the problem... Then the 21st day of the pack i missed that pill so took it the 22nd day i started the pill pack on a sunday so i took my last active Saturday pill on a placebo sunday pill ive done that before and started towards the end of the placebo week but i completely missed it this time... Today 1/1/2019 i am experiencing nausea and stuffy nose and 2 days prior i had some cramping... 3 hpts have been negative but its possible ive been testing early... Really dont want a baby right now but cant do much if i am because i am going to take responsibility for the mistake i made... Can anyone tell me what they think? If i don't start on monday im going to the obgyn