Try this easy solution.
Use your working memory problems to your advantage in this type of situation.
First of course you look for the lost item (ask for help if possible). It’s ok to be upset but try not to get too upset especially if people are helping you look (to spare their feelings).
If the item can’t be located then use your poor working memory as your super power.
Let go of the problem. Move on. Move to the next activity. Don’t think about it very much anymore. Acceptance. Poor working memory can help with that because once you move on and focus on something else you can basically “forget” the problem.
Poor working memory can help you live in the now.
So accept it. Move on. And change topics. Live in a different “now”.