Period regularity, tmi

So short background first, started bc at 14, on the shot 3 years, pill 1, then shot for 3 more. Got off everything and I was diagnosed with PCOS. For over a year after I didn't have a period at all.

So my doctor put me on the skyla iud. It's a few months shy of the first year now. For the last 3 months I have been on time and actually having a period for the first time in so long.

But what I am wondering about is if anyone else has had a similar experience and noticed maybe light bleeding at first and then chunks of tissue, then maybe a heavier flow after.

The first period I had on the iud I had cramps so bad I couldn't walk and had such a large piece of tissue I thought I miscarried. But after determining that wasn't the case I've noticed this as a pattern. Could this be temporary? Will it go away eventually the more periods I have?

Before I was ever on bc I was never regular with my periods so really this is a first for me.