Katie Clark -- a star of the hit show "Bringing Up Bates" -- is going through a tragedy ... announcing she lost her pregnancy.

The reality star announced the news on social media Friday ... sharing a clip which begins with her finding out she's pregnant.

She then buys baby clothes and tells her husband Travis the news ... with the two happily embracing -- before the clip changes drastically.

The second half of the clip takes viewers into a series of hospital rooms ... before showing a sobbing Katie who tells her friend she lost her baby.

Katie captioned the video, "I will spend the rest of my life missing you 🪽."

Katie and Travis were expecting their third child. Their daughter, Hailey, turns three next month. Their son, Harvey, turned one in September.

"Bringing Up Bates" ran from 2015 to 2021 and chronicled the lives of Gil and Kelly Jo Bates raising their 19 children.