Ovulation bleeding? Implantation? Spotting?

Cycles are super irregular. Periods are usually 7 days and heavy. However, I have been "spotting" I have been having pink like blood with some disharge but not enough to fill pad. It lasted for 2 days with awful cramps. Now, I'm experiencing brown spotting. Not a lot though and cramping went away. I've taken pregnancy tests and they all came back negative could it be implantation bleeding or just spotting? Confused . . 😩