Sorry that you are not seeing the post that you just posted. Here are some things that you can do to see the post -

• Refresh the browser or the app and see if it shows
• Please check ALL GROUPS FEED. Sometimes if you select individuals as recipients, then you will not see the post in the class feed, you will see it in the All Groups Feed. 
• If the post is still missing, please write to [email protected] with the post's title and report the issue.