My Sent folder is missing most of my sent emails

My sent folder shows 85 sent emails. The settings I have for Outlook are to keep all sent emails on the server. I'm using IMAP connection. 
Where are all of my sent emails? 
I tried this link, but there were only 50 emails there, and I don't think any of them were ones I sent. https://www.xfinity.com/support/articles/recover-deleted-email

Help!