Christina Applegate Thanks Fans for Concern After Hospitalization

Christina Applegate gave her fans a fright last week when it was revealed she'd been in the hospital.

TMZ broke the story ... the actress was admitted to an L.A. hospital late last month, but it's unclear why or how long she was there.

On Monday, she took to Instagram to reassure fans she's OK and thank them for the "outpouring of love and well wishes."

CA shared a shot of her book, "You With The Sad Eyes" and a mug that says "Kissy Kissy" ... acknowledging in the caption that she's constantly dealing with health issues.

She wrote ... "I’m a strong chick and I’m getting stronger and better every day. I’m taking a moment to focus on my health, but I’ll be back with more to say soon enough."

When news broke about her hospitalization, Christina's rep had "no comment" to us about whether or not she was still there or what she was treated for, before adding ... "She's had a long history of complicated medical conditions that she has been refreshingly open about, as evidenced in her memoir and on her podcast."

Remember ... on March 31, the actress' "MeSsy" podcast cohost, Jamie-Lynn Sigler, announced the show would be going on a hiatus because both she and Christina would be on book tours.