AF 3 days late, still getting BFN

okay so this is the first time I've ever been even close to thinking I'm finally pregnant in all the time I've been TTC.
AF is 3 days late, but I'm still getting BFN's!! could this be something to do with the fact my cycle is so short? It's only 22 days? I have no signs of my period at all.
Hope you can help!✨