18 day cycle???

Natalie • 25|| Married to my best friend♥️|| Elijah 3/19 ♥️ Baby #2 11/22 || Born-again Christian||

Back story, had my daughter 13 months ago, 14 on the 17th. I stopped breastfeeding at 12 months, her birthday to be exact. I had my first period at 6 month PP(I thought it was 9 months PP)

...And now for some reason out of nowhere I'm having my period only on cycle day 18. I do have Hashimotos Hypothyroidism and on armour thyroid 90mg. Thoughts? Has anyone else experienced this? I'm used to irregular periods but this is a new one for me lol