The Geordie Shore star, 25, had been due to sign copies of her new weight loss book at WH Smith shops in the UK this week but her appearances have now been postponed.
A rep said: "Due to ill health Charlotte Crosby has been signed off from work by her doctor. Therefore all events have been postponed. We will reschedule as soon as possible. We apologise for any inconvenience caused."
Charlotte hasn't referenced her illness on Twitter, although did tweet on 15 April: "Fingers crossed tonight I will sleep! Last night was BRUTAL."
She followed that up the next day by saying: "You really couldn't write this past week I've had........ Wow." The reality star also complained that she was missing exercise and couldn't wait to get back into the gym.
Charlotte will resume promoting book Live Fast Lose Weight when she is better again. The advice book is packed with her own fitness and diet secrets which helped her lose weight over the years.
"I always get asked: Did you cut out alcohol?.....NO. Did you do a fad diet?.....NO. Did you cut out carbs.....NO. SO HOW THE BLOODY HELL DO YOU LOOK SO GOOD BUT STILL GO OUT AND HAVE SO MUCH FUN?!?! THE SECRETS OUT GUYS.
"Here it is: What I EAT. What I DRINK. How I manage those HANGOVER cravings. My Cheat days! My TOP TIPS on HOW to lose weight FAST. ALCOHOL CHEATS. What to wear. MOTIVATION ESSENTIALS. Exercise MUST DOs.
"My full weight loss journey is in this book, the highs the lows, the blood sweat and tears, And what kept me going to achieve my DREAM body! #LiveFastLoseWeight the secret is yours FINALLY."
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