Cramping on and off

Hey girls I want to know if some of you experienced cramping like AF cramp but lighter and on and off before you get your BFP? I'm actually 4 days late and having these light cramping since friday, also my boobs feel heavier than normal and my nipples are super sore but I have these symptoms before AF normaly. But the cramps are not like I normaly have. I took a hpt (FRER) friday night and it was negative. So I don't really know what to think. 😞