Reenable Spotlight

I noticed that spotlight was using a lot of CPU and I did not have time to debug it, so I disabled spotlight with this command:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

Now I want to reenable spotlight and debug why it is non-stop indexing my drive, but I can't figure out how to reenable it.

$ sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
/System/Library/LaunchDaemons/com.apple.metadata.mds.plist: service already loaded

But when I search for anything I get "No Results".

Here is my configuration:

Spotlight System Preferences - Search Results Spotlight System Preferences - Privacy

How do I get indexing reenable?

[EDIT]

I tried one of the suggested answers with this result:

 % sudo mdutil -a -i off
Password:
/:
2020-09-03 15:35:44.980 mdutil[33360:1381738] mdutil disabling Spotlight: / -> kMDConfigSearchLevelFSSearchOnly
    Indexing disabled.
/System/Volumes/Data:
2020-09-03 15:35:45.026 mdutil[33360:1381738] mdutil disabling Spotlight: /System/Volumes/Data -> kMDConfigSearchLevelFSSearchOnly
    Indexing disabled.
/Volumes/MBP15 Time Machine:
2020-09-03 15:35:45.060 mdutil[33360:1381738] mdutil disabling Spotlight: /Volumes/MBP15 Time Machine -> kMDConfigSearchLevelFSSearchOnly
    Indexing enabled. (Indexing level may not be changed on volumes which have a Time Machine backup)
/Volumes/MBP15 Time Machine/Backups.backupdb:
2020-09-03 15:35:49.728 mdutil[33360:1381738] mdutil disabling Spotlight: /Volumes/MBP15 Time Machine/Backups.backupdb -> kMDConfigSearchLevelFSSearchOnly
    Indexing enabled.
 % sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
/System/Library/LaunchDaemons/com.apple.metadata.mds.plist: Operation not permitted while System Integrity Protection is engaged
 % sudo mdutil -a -i on
/:
    Indexing enabled.
/System/Volumes/Data:
    Indexing enabled.
/Volumes/MBP15 Time Machine:
    Indexing enabled.
/Volumes/MBP15 Time Machine/Backups.backupdb:
    Indexing enabled.

Open Terminal window from LaunchPad.

First, turn off Spotlight:

sudo mdutil -a -i off 

Next, unload the metadata file that controls Spotlight’s index:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist 

Use the following command to re-loads the index :

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

As a last step, turn Spotlight back on:

sudo mdutil -a -i on 

After a few minutes to rebuild the index, Spotlight should be functioning as normal.