To reinstall, I will have to 'Remove'  the extension using Add-on Manager. Will I get back by earlier dials? If not, how to restore them?

I am using FVD speed dial for a long time on Firefox on windows 8.1. Current version of firefox 55.0.3 (64). On September 25 Speed dial was working correctly. On 26th morning, when I started laptop and firefox, the Speed dial disappeared.

Please let me now how to restore it. It has many dials in several groups, collected over years.