MacBook Pro (Retina, 13-inch) El Capitan I have a Macbook Pro Retina 13 inch. 
I have recently lost my notifications in the notification centre. The "
today" tab functions but my "notifications" bar has nothing. The banners from notifications pop up but they are not saved in the "notifications" tab. I have attempted killing and restarting the notifications centre through Terminal but to no avail. Please help! TIA
Check in your System settings >> Notifications on the left side on the Panel if Do to disturbed is in any way activated. Also check from which app you need Notifications and activate it. 

Also you should look in the settings of Security >> Privacy if Notifications from your apps are disabled.