Increased CM before BFP??

Hi ladies! I am on cd30, 13DPO. Tested this morning and got a BFN. However, today had a lot of ewcm when using the restroom. Have had a lot more than usual for the past few days, considering where I am in my cycle. It has also had a slight yellow tinge at times. Got a negative opk. Usually before AF, I am dry. Anyone had this experience and gotten their BFP