You should always do a Nandroid backup before flashing new ROMS, because losing all your data is an expected outcome.
Did you set up Google to backup your apps and data? If you did, Settings>Backup and reset should help. Otherwise, go into Google Play Store, click on the down arrow near the upper right corner, and then click on the All tab and reinstall all your apps manually.
I'm not the lowest of the low, but I am the slowest of the slow (49.6 mpg over 38k miles in Scion xB)