The 33-year-old actress took to Instagram to share several photos, including two featuring the script for the show's final episode and another of her in tears.
In her first pic, Cuoco gave fans a glimpse of the milestone script, complete with the words "END OF SERIES" typed out on it.
"Yea, didn't sleep," she captioned it.
The actress, who plays Penny, the wife of Leonard (Johnny Galecki), on the long-running CBS sitcom, followed that up with a photo of herself crying after the first table read for the last episode.
A third photo showed the script on a table next to Cuoco's nameplate. Crumpled tissue paper, presumably used by the sobbing actress, covers its pages.
"Prepare yourselves ... for a finale that has truly given me a loss for words," the actress wrote in its caption.
Some of Cuoco's past and present co-stars commented on her emotional posts, letting her know the upcoming finale has them feeling just as blue.
Melissa Rauch, who plays Bernadette on the series, wrote, "Same, sister!!!"
Laura Spencer, who played Raj's girlfriend Emily from seasons seven to 10, shared several heart emoji.
Meanwhile, actress Courteney Cox, who recalled feeling just as sad when "Friends" ended after a decadelong run in 2004, sent a sweet note to her pal.
"Awww I remember that feeling," Cox wrote, "and you guys have been together even longer."
"The Big Bang Theory" will bid farewell to fans with a special one-hour episode May 16 on CBS.