Oh sorry for the late reply. I missed this.

I'm currently using the head_block so I normally get the notifications within few seconds. I guess it was some server issue before.

So do you want to deactivate your account notification temporarily?
/cancel_monitor command is for canceling notifications of other users' posts.
If you want to deactivate all notifications including yours, you can use "block" or "mute for a while" feature on Telegram.