TMI‼️ extremely clotted spotting/period???

*keep in mind that my period has slowly digressed from being heavy/normal to very light the past several months* My period was supposed to start today, but yesterday I started having dark bloody spotting (it was dark like old blood) A couple of hours ago it seemed as though it had gotten heavier, so I figured I could wear a light tampon. I just took it out and it was covered in nothing but dark blood clots...like I used a piece of toilet paper to get it off & the tampon underneath the clots was still white. This doesn't seem normal, right??? What should I do?