Google Nexus 5 :: Why Don't Have Incoming Text Messages After Low Storage

So for weeks I've been dealing with a low storage space issue on my N5. I've been hovering at about 500MB of free space. I delete some photos, some cached data, etc., and get some more breathing room for awhile. (An aside: there's a specific app that is using way too much data storage and the amount keeps going up and up; I'm trying to resolve that issue without deleting the app.)

Occasionally I've received the system alerts about no new voicemail downloads, possibly no new message downloads, etc. I'll clear some space and those alerts go away and everything continues to seem to work fine.

This morning I got the low storage space alert(s), deleted some stuff, eventually got a handful of new email notifications, but for the past 6+ hours I've received no new txt messages (I use Messenger app for sms). I currently have 553MB of free space, I'm getting email notifications, and txt messages I send out are successfully received.

How do I resolve this? My N5 is unrooted. I've tried leaving it off for awhile, and have obviously rebooted it. Could this just be some network issue? (I'm on tmobile.)

(btw, I somewhat recently backed up and deleted a bunch of sms/mms messages, so there's only about 8000 currently on my phone, taking up about 165MB of space.)