No AF at 19 dpo... Any ideas?

Has anyone gotten a positive test after 19 dpo? I have been taking tests every days and only getting BFNs. There is no sign of my AF coming and to make it more confusing I am feeling slightly nauseous at times, super tired out of nowhere, peeing more often and a stronger sense of smell. At this point I feel like I am imagining it all. This is so frustrating!