TMI: Never experienced this before on my period

[ThisLilacWasp]

Sorry in advance for the TMI photo but I am slightly confused / concerned over this.
I have PCOS so my periods can be a bit irregular in the sense of cycle length but I always have a period. We haven’t been “trying” as such more so not being as careful anymore.
I am on day1 of my period on a 38/39 day cycle and it is quite light which is strange for my day 1 but then this “fell” out of me in the toilet. Has anyone else had this?

Google has said anything from decidual cast to sign of ectopic pregnancy.

Any advice would be great thank you!

It looks like a shedding from the lining of your uterine wall.

In other words, a product of your period.

As PP said, uterine wall or possibly part of/a fibroid.

I had something similar happen to me when I was a teenager - at the time, I was freaking out, but on reflection, it probably was just a very large piece of uterine wall. If it helped, I 'washed' mine in the sink to get a better look at it and kind of ended up looking like a large, thin chicken breast.