I deleted apps but it didn't free up space?

I got a notification saying my iphone's storage was almost full so i clicked manage storage to see which apps were taking up the most space. My twitter app seemed to have taken up 5.2GB (i'm used to it building up after a while) i deleted the app and i was going to reinstall it in a moment but i checked my storage to make sure it freed up space but it didn't? Do you think my phone is just glitching or something?

If you didn't empty the trash, the file(s) are still there. Empty the trash, then try again.

What I noticed on my iPhone is that when I go to delete an app or anything it might take a bit of time to update how much storage there's.