Period or IB?

So my husband and I are trying for our 3rd and I don’t remember having IB with my first two. I started bleeding Monday, it was only spotting. I’ve been cramping ever since. But today I got out of the shower and put a tampon in and it got filled up by the 8 hour mark. Anyway, I’m trying to find out if it could still by IB or if it is my cycle.

I’m not supposed to start until the 28th and I’m always in time. Never early.

Opinions please?