I have had the exact same thing today. At least two apps (Uber and Galaxy Wearables) were not showing in my apps drawer when I swiped up on the home screen. I could search for both apps and run them. Uninstalling and reinstalling Uber worked for that, but of course, you don't know what else is missing until you need it! I am using GoodLock and the HomeUp customisation tool. I went in to HomeUp and turned it off, and I could see the missing apps again. When I turned HomeUp back on, thankfully they were still visible. Hope you manage to sort it out.
Thanks @walkerx. I didn't know that, although it wasn't the case here. Neither of the apps were in a folder and I was able to search for and run both missing apps; one of which was used regularly. However, it may have been Uber was in deep sleep before searching for it, but even running it didn't bring it back to the app screen. Reinstalling it did work, which was OK when I thought I was only missing one app.
