Periods 2 1/2 weeks late, am i pg?

Hi there, this is my first time on here, basically I have 2 beautiful daughters and when i fell pg with them i didnt know only i had a missed period with them, that was the only reason i knew.....So anyway, I have been on my pill Microgynon 30 since i was 15, (came off it properly when i was pg with my girls) So this time round I got married 5 weeks ago and was gonna come off the pill very shortly, so for the last 5 weeks i was taking it very irregularly, missing maybe 2-3 pills each week, finished my last pill coming up for 3 sundays ago now, was supposed to get my period on the wednesday after taking the last one on the sunday, it did not arrive!! me and my hubby had sex on the wednesday when was suppose to get period, I was very wet before sex quite dischargy i would say, then on the fri, sat, sun i had the smallest amount of really light pink blood, like spotting, the following wed after sex i had what was like brown discharge, with no smell etc, like the end of a period type thing, Little worried as i always get my period after my last pill always have done, even when im not on the pill i am also very regular, never missed in my life apart from my other pg's.

I have had nausea which lasted for a week and a half, tension headache then aswell, i have a brown ring around both my nippes, feel very bloated, stretching/cramping in lower abdomen, etc the thing is i have done seven tests all negative!!!!!

Was it possible for me to get pg on the day my period was meant to come but it didnt??? PLEASE, PLEASE HELP, dont know what to do!

Any answers would be very much appreciated, sorry this is soooooo long lol xxxxx XD