Possibility of downgrade

After the last upgrade my mozilla runs significantly slower and all my tabs work as if my system runs on windows 3.1. My dials take forever to show, every new tab i open takes forever to show, my settings keep on defaulting every time i make a change (e.g, at background options i choose the stretch option at image source and it keeps on going back to parallax....I really need a downgrade. This update really destroyed my existing setup and i cannot enjoy the app anymore.