Late and BFN

I'm getting a little miffed and need to vent!

My longest LP has always been 13dpo. I'm 15dpo today and still got a BFN this morning! Started spotting the day my period was expected but it has been extremely light and my bbt is still well above coverline. Perhaps I've implanted a little late and that's causing the spotting?

Tender boobs - especially my nipples, having dizzy spells, feeling extra tired mid-afternoon the past few days and napping after work, and just overall feeling off. I've been guilty of symptom spotting in the past so I'm not really sure how much I trust what I'm feeling.

What gives? I really don't want to be one of those people who never get a positive hpt and have to be anxious and worry until I can get in with my doctor for a blood test. Trying to not get my hopes up.