Did you try clearing your cache? Most of your work should be saved, as long as you remember your login & password, you can try signing back in. To clear your cache:
Tap the button at the bottom of the screen, then select “Settings“. Scroll down and select “Clear all cookie data“, “Clear cache” or “Clear history” as desired (you probably just need to clear cache, you can try history if that doesn't work). A dialog should appear where you can confirm your selection. Tap “OK” to proceed. Then try logging in again and hopefully it will work!