If you implant at 12 dpo when should you test?

I tested at 14dpo but I got a negative or maybe a VFL. I’m unsure. Well now I am 16dpo and still no sign of aunt flow. However, my periods are irregular at times.

My last period started on the 18th of August.

The one before that started on the 17th of July.

And in June it started on the 26th.

So in all honesty I could be having a late period.

But I usually have cramps a few days before I start. But all I’ve been feeling lately is insomnia, and fatigue, and slight nausea. Obviously too early for pregnancy symptoms, but these symptoms definitely aren’t normal for my menstrual cycle. Any ladies out there get a negative at 14dpo but a positive at 16dpo or maybe 18dpo?