How to monitor icloud backup progress?
After 5 days you might need to figure out where the backup is hanging. 45 gb means you have significant data getting backed up. Also, there’s not a good way to monitor things, so you might need a a split half search. 

In this case I would disable backup of half the items and then see if backup completes in an hour or two. If not, disable half of the remaining items and repeat. 

See this article for how to selectively back up some apps and data. - https://support.apple.com/en-us/ht204247

Once the backup succeeds, re-enable things half by half. 

Worst case the backup never works and you have to back up to iTunes. Best case the smaller backup gets you past the log jam.