Implantation bleed experience

Just looking for someone with experience with IB. I had brown/rusty spotting yesterday (6dpo) and now today (7dpo) it’s dark red and more than spotting but definitely less than a period. It won’t actually fill a pad or tampon but its very present when I pee/wipe. I ’m also cramping.

I’ve been tracking bbt & using opks so it doesn’t seem like I got ovulation wrong this cycle. I guess what I’m asking is.. can IB be more than spotting like this or is something weird going on?

Chart posted below: