Af 10 days late still BFN!

Danielle
Hi everyone, just wondering what's the longest someone has gone before finally getting a BFP after a missed AF? Had a miscarriage in august and not sure if I'm late because of that or whether I'm pregnant but hormone level isn't high enough yet, been feeling really nauseous the past couple of days and a little bit of cramping in my stomach. would appreciate other people's experience x