My fiance thinks my period wasnt really my period. He thinks i may be preg?

Okay so my cycle was 37 days, and it was due today but i started spotting very light pink mucousy discharge tuesday night. I never spot. the next day (wed) it was light still but i thought it was just flo. well (thursday) it stayed the same looked like it was tryin to go medium. then friday it slacked alot back to spotting. then that night it went to brown mucousy discharge. and now its saturday and its very light brown discharge. no hint of pink or red. I mean a light brown. He thinks it isnt flo because i've been an emotional wreck. I cry over the smallest things and im not a crier. I had a belly ache today while i was at work and i kinda felt nauseous. I felt small cramps today also. Any ideas?? We did do the deed Oct 10th when we went out of town for the weekend. No birth control or condoms. Not too worried.