So confused

Louise • 34 🇬🇧 TTC #1. Engaged.

So I am about 10 dpo (verified using opks) and have had some spotting today. I’ve taken a pregnancy test and it’s negative. The app says I’m 4 days away from my period. What’s going on? I realise that I’ll find out either way over the next few days as period will either kick in fully or not but just a bit confused so wanted to hear your thoughts as I’m new to all this! Thanks x