Try to delete all the affected apps and reinstall them. Also check the in-app settings to see if its something in there causing it. Maybe check the system settings too to see if there is a setting that could be affecting the notifications.
For Facebook specifically definitely check the in app settings.

If it's system apps(Messaging, Phone, etc) that aren't showing notifications then back up your data and do a factory reset. This will surely fix the issue.

Jone wrote Try to delete all the affected apps and reinstall them. Also check the in-app settings to see if its something in there causing it. Maybe check the system settings too to see if there is a setting that could be affecting the notifications.
For Facebook specifically definitely check the in app settings.

If it's system apps(Messaging, Phone, etc) that aren't showing notifications then back up your data and do a factory reset. This will surely fix the issue.

uninstalling and reinstalling didn't work for facebook. I think I have to factory reset my phone. Gah

Out of interest do you have any icons across the top of your screen?

Asymmetrical wrote Out of interest do you have any icons across the top of your screen?

[ Register or Signin to view external links. ] that number at the top left is a battery life saver Icon

Asymmetrical wrote Out of interest do you have any icons across the top of your screen?

[ Register or Signin to view external links. ] that number at the top left is a battery life saver Icon

can be alot of stuff.
maybe they got turned off?
if you have custom rom like me i have a setting to stop "spam" notification like a firend trying to blow your texting app up

go to settings > apps> an clean data/chache

reboot

throw your phone at a friends face an make the galaxy wistle sound.

lol there is alot to do you just need to figure out what app is messing with your notifications

frostt wrote can be alot of stuff.
maybe they got turned off?
if you have custom rom like me i have a setting to stop "spam" notification like a firend trying to blow your texting app up

go to settings > apps> an clean data/chache

reboot

throw your phone at a friends face an make the galaxy wistle sound.

lol there is alot to do you just need to figure out what app is messing with your notifications

Sorry I haven't been on, but I like the last idea about throwing my phone at a friends face and making the Galaxy whistle sound. but everything's working, I just factory reset my phone and it worked, sadly I lost everything but that was to be expected