When I collect money, food, feed dragons etc I’m hardly ever getting coins. I log in and collect, then the next few times I collect everything I get nothing. Is this normal?

Hi and welcome to forum :)
did you chekec this event topic
https://forums.socialpointgames.com/topic/5977/mini-oni-island-event-12-mar-15-mar-2018
there is a max of coins you can get and there is time frame - every 8 hours -