BBT spike could it be pregnancy?

Amanda

Ok ladies a little input please! My temps spiked this morning.. 6dpo 97.7F. .7dpo 97.8F 8dpo 97.5F 9dpo 97.2 this morning 10dpo 98.0F? What could have caused this? AF (Aunt Flo - menstruation/period) is due on the 10th or 11th I took a PG (pregnant or pregnancy) test yesterday morning and it was BFN! Could I have tested to early or is this just something that happens before AF (Aunt Flo - menstruation/period) arrives?