Cramping for 4 days!? 😵

Stephany • TTC #1 for 6 years... Diagnosed w/Endometriosis 2015
Okay so glow said my period was due on the 23rd but Ovia says it's on the 30th.... Either way I have been cramping on and off throughout the day for 4 days now with no sign of AF.... This is totally not normal! I normally cramp for maybe 2 hours and then AF shows for face. Took a test today and it was BFN..... What next? Any advice?