Gassy! PMS or Pregnant?!

Sarah
AF is due Wednesday, however I had on and off cramping all day on Friday, along with heartburn. Still getting negative tests, but suddenly I'm incredibly gassy. It's disgusting, but I've been slightly constipated as well so I'm just curious if this happens to anyone else prior to starting their period or possibly early pregnancy?! I'm 11dpo today, so I'm hoping AF doesn't show!