AF due 21st March

Khloie 🇬🇧 • Baby boy 10th Dec ‘17 🐒 Baby girl Aug ‘19 🤱🏼
I'm due on in 2 days. I'm 11dpo according to OPK's I took. I've taken a test this morning BFN not even a hint of a line.
I'm feeling nauseous this morning really dreading my work out. I have thrown food up a few times and have been constipated for a few days. 
Usually the week before I'm due AF my boobs are sore & I have spots and cramps and I haven't had any of that aside from a few gentle cramps a few days ago. 
What do you guys think? Keep testing?