Having menses-like cramps but no menses yet

Hello! My menses is expected to happen in the next few days and I’m having bad cramps for a few days now. I took the menses panadol (pink panadol) but my cramps has not subsided. Been feeling hungry and really moody! I just took the home pregnancy test and it’s negative. I just gave birth 4 months ago and had unprotected sex. Please advise if it’s just PMS or early pregnancy symptoms?