5 Days late....not even a sign of af but still BFN?!

So normally I'm regular like click work...never late, never missed a AF...thought a week ago in was having symptoms; crazy heartburn, sore boobs, mild off and on cramping, moody then it went away...so now everyday I've been holding my breath and still nope....poas a few times, passed the first 2 as too early. Third and fourth were on Monday and Wednesday and still nothing...not even a hint of a line. So today I'm like its gotta show something....and a bfn. WTH?!!!...I have a doctors appointment for Dec 5 but I know it feels like such a long time away. Anyone else had something similar and then find out they were pregnant??? I'm feeling pretty desperate for some support or answers!