Kelly Stafford returned to the hospital days after a scary, 12-hour brain surgery ... saying the pain had gotten too much to handle as she recovers from the serious procedure.
The Detroit Lions superstar QB's wife had surgery to remove a brain tumor over the weekend ... and managed to return home in time for Easter Sunday.
Kelly -- who has been very open about the challenges she's faced since the tumor was discovered -- says she was taken to the emergency room Wednesday morning ... after experiencing "pain and massive headaches."
"I thought I could power through the pain and massive headaches that were challenging me throughout the day," Kelly said.
"I thought I could do it. They told me tapering off the steroids was going to be very difficult."
Kelly says she looked to her husband for support and thought his strength would help her get through the suffering ... "I told myself the pain would succumb to me, I wouldn’t succumb to it."
"I was so wrong. The pain got so far ahead of me I couldn’t keep anything down, including meds. I ended up in the ER very early this morning, back on steroids and pain medication."
"At first, I felt like I had failed, like I couldn’t handle it.. but what I really failed at was listening to my own body. A lesson I feel like I am going to have to keep reminding myself of."
Kelly says she'll stay in the hospital overnight -- hopes to return home Thursday -- and thanks everyone who has reached out with kind words during her recovery.