14dpo bfn want to test tonight. How long of urine hold & whats best HPT

Cycle day 27 14dpo bfn.. how long of a urine hold to do in evening. My Dr. Said to wait and test never before 28 days. Any thoughts. I have egg white mucus really weird. Od on 14dpo using opk, checking cervix have up &down temps. brown implementation spotting 8-10 super light. Anyone get a Bfp 15dpo.. no AF in sight. High soft cervix. Im going out of my mind.. Any thoughts

Praying this time I'm prego. Never had a cy or lime this and up and down temps only 3 below cover line