iPhone Calculating category size - stuck

[TTTony]

I'm trying to check app sizes by going "iPhone Storage"
There "Calculating category sizes" blinks forever.
Checking the app list, scrolling to the bottom, I noticed that the green "Phone" app icon never stops searching, rolling and rolling, forever.
Its "Document and data" size is -311 kb.
How can I fix this? Asking because I wonder if this unending search will run in the background draining power.

YES, I've tried to restart the phone AND it isn't jailbreaked, and never will it be.
Thank you!

 

[TTTony]

The bar showing sizes of Apps, System and Other didn't work either. It was like this all the day. I just uninstalled some arbitrary apps, and suddenly it works again. The Phone app shows size 25kb, not -311kb as before. Have no glue what happened, and what fixed it.

Edit: Also noticed that _Settings_ had very high battery usage, 35 %. Something was wrong, seems to be ok now.