Advice Needed

Sharon • 42 & TTC #3 #1 for my gorgeous SO hoping for a girl as have 2 boys 14 & 18
I'm currently cd33 15dpo with very slight spotting did a hpt yesterday n got a bfn still no sign of AF and this morning my temp shoots right up which has really knocked me for six n is confusing the the hell outta me, does anyone know what this could b??