Frustrated, need support.

I've recently become irregular. Luckily I chart religiously to better understand my body after birth control... I'm currently on CD48, I ovulated CD 30 so I'm 18dpo. I've had nothing but BFNs. Patience is the hardest thing for a person when TTC. All I can do is pray I have a sticky baby that is just being shy. Please tell me someone has experienced a pregnancy and it take more than 18dpo (with high temps) to detect.