Hey _anders_o,
We appreciate the information. Is notifications for the Facebook app enabled. If so, disable it and see if that resolves the issue.
If it doesn't, we recommend unpairing and erasing the Apple Watch. "Before erasing all content and settings on your Apple Watch, your iPhone creates a new backup of your Apple Watch."
Afterwards set up the Apple Watch again. Below are the steps to unpair and erase the iPhone.
1. Keep your Apple Watch and iPhone close together as you unpair them.
2. Open the Apple Watch app on your iPhone.
3. Go to the My Watch tab and tap All Watches.
4. Tap the info button
next to the watch that you want to unpair.
5. Tap Unpair Apple Watch.
6. Tap Unpair [your Apple Watch name].
7. For GPS + Cellular models, choose whether to keep or remove your cellular plan.
* If you want to pair your Apple Watch and iPhone again, keep your plan.
* If you don't want to pair your Apple Watch and iPhone again, remove your plan. If you aren't going to pair with a different watch or iPhone, you might need to contact your carrier to cancel your cellular subscription.
8. Type your Apple ID password to disable Activation Lock, then tap Unpair.
You can also review the steps here: Unpair and erase your Apple Watch.
Afterwards, follow the steps in this article to set up your Apple Watch again: Set up your Apple Watch.
If issue persists, we recommend contacting Apple support in order for them to further look into this issue with you. You can reach out to them here: Get Support.
Take care.