I definitely went thru it as a kid. Going to daycare and preschool was a huge source of anxiety for me, because either my mom or dad would drop me off there, not return for hours, it was nothing like home at all, social interaction was forced on me, and I was only allowed to have my emotional support plushies at naptime. And the emotional support items I brought with me that were not plushies were disallowed completely - at the preschool I attended, they had some kind of weird rule about only allowing soft toys at naptime....which was weird cuz during free play they had all kinds of "hard" toys like cars, dinosaurs, balls, Legos, and blocks.
Not that I cared about any of those much; I only wanted to stay home, with my parents, with my own toys, and that was that.
Anyway.
My mom got the idea to give me a small drawing of the face of a clock to keep with me as the day went on...that is, a drawing of what the clock would look like when she would come to get me. The idea was that whenever I felt separation anxiety during the day, I would look at the clock picture and feel reassured that my mom would come soon. It sort of become a transitional object of sorts....I must have worn that clock picture ragged after awhile.
And, I know I've mentioned this before, but I went thru separation anxiety with my aunt, too....when she would leave after a visit, or when I had to leave her, I would get really depressed and cry a lot for about a week afterward. It drove my mom crazy. I had plushies of Pikachu and one of the Seven Dwarves that my aunt gave me that I would turn to for comfort when that happened.
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I wish Sterling Holloway narrated my life.
"IT'S NOT FAIR!" "Life isn't fair, Calvin." "I know, but why isn't it ever unfair in MY favor?" ~ from Calvin and Hobbes