TTC On progesterone-implantation bleeding?

Been TTC for 7 months. I have been on progesterone only day 14-28 to try and regulate my irregular cycles. This is my second cycle on progesterone. Yesterday was day 23 of cycle and started getting intermittent pelvic cramping and then the bleeding started. I would not call it light bleeding, I am using a tampon and changing it about every 4 hrs. Still have backache like a period. Anyone experience this and what happened with you?

The progesterone is supposed to regulate my periods (and it worked perfectly last cycle) so I’m confused as to how this would be a period and hoping it’s just implantation bleeding? But a lot of the posts I’ve read everyone says “scant bleeding” and I wouldn’t call this that. I ovulated day 12 of my cycle.