Firefox just broke all add-ons because they forgot to renew the certificate.
There is now a lot of articles about it over the internet, see for example: https://www.ghacks.net/2019/05/04/your-firefox-extensions-are-all-disabled-thats-a-bug/
The official tread where the issue is being tracked and solved is here:
For now, I would suggest you - don't panic, don't reinstall anything, the best thing to do is doing nothing.
Since millions of people is affected, this kind of serious issue will be promptly fixed by Firefox team.
If you cannot just wait and enjoy Saturday and you really need your dials page now, you have several options.
The easiest way is using the cloud dials page - but this works only if you have created cloud account: https://group-speed-dial.fastaddons.com/cloud
Others are not so trivial or safe, so please let me know if you want know more.