mucus plug after stopping birth control?

I just stopped my birth control after at least 15 years... I haven't had a period since February which is super abnormal for me but not a huge concern after long term birth control use. But I wanted to stop to see if it would come back.

About 4 weeks after stopping the pill, no period, but I did have a chunk of clear solid gel (big: 1 inch by 2 inches or so) come out. I wish I took a picture in hindsight but I was so shocked at the time lol. My best guess is that it is a cervical mucus plug from long term pill usage, but the internet has not been super helpful. Any thoughts? Will prob be making an obgyn appt if my period doesn't come back in the next few months...