So confused about my cycle… m/c?

I’m not on BC, have been having regular sex with my partner. We hit almost every day in my fertile window…

My period started one day early, with really really slow spotting for two days. Then I had a wave of the worst cramps I’ve ever had in my life, combined with a heavy flow for eight hours- basically one tampon. It was bright red, dark red, and brown. There was some “texture” to it.

Then the next day I went back to a super light period, and the next day I spotted a tiny bit.

So my period was really only one day of horrific cramps, and a couple days of some spotting. I don’t usually get bad cramps, and never as bad as they were.

Could this have been an early miscarriage? There’s no way this was implantation cramping right? Far too painful for that?

I’m 35 and am not very fertile- I say that because I’ve been in another LTR without pregnancy despite not using protection. I also have been told by doctors that it will likely be tough for me to get pregnant.

Just looking for insight and advice from some people who may have gone thru this.

Thanks

💕