Anyone doing the 5:2 diet

Hi anyone doing the 5:2. I started middle of last week. Anyone had successes. Feels strange to be able to eat normally on a feast day and does it matter if you are over your total cals on a feast day or if you are under on feast day. Had my first fast day last week and lost 2lb but not weighed after feast days .

Also have under active thyroid does this affect it.
Sorry all the questions.