How does one differentiate between implantation bleeding and period?

There are so many contradicting answers on the web.

Anyone who has personal experience care to share? When they thought or answers on the web points clearly it’s period and not IB but it turns out it’s IB that you’re having and you get a BFP after that?

I’m on a regular 31 day cycle. Yesterday at cd30 I had some pink or light red spotting. But today it’s more.. but still a light to medium sort of flow. I have been nauseous and wanting to throw up for a few days now, been having really strong craving which I don’t usually have, and I have had days leading up to yesterday where I did not really have an appetite to eat which is not normal too, my tummy doesn’t feel like the normal period sort of cramps. But there’s still cramps..