Uh oh I'm late

Hello everyone! So I'm 20 days late... I usually cramp really bad before my period begins but there has been nothing. I mean some small cramps in my abdomen have happened but that's about it. I've had diarrhea, spotted, been grumpy, have a tender chest. I haven't been stressed or anything either. I took a clear blue test but it said negative. But now I'm not so sure. What are your thoughts on this?