Thank you Session Manager Rated 5 out of 5 stars
I started my Firefox 55.0.3 this morning and found none of may tabs. I had many many "New Tab's" but none of my many many tabs that I have been using. I looked up options using Safari and didn't have much success. I was going through my history files and restoring them one by one. After about an hour I happened to remember an add on I had. Session Manager. I fired it up and was pleasantly surprised all my tabs were restored. Thank you session manager!