The thing you are waiting for is to understand your tank, perhaps buy the test kit yourself that way you will learn to understand what is actually being tested. It takes a while to get a grip on everything to begin with, but that is what you need to do before adding any more fish.
Get your damsel eating if he isnt already, if you cant get 1 fish to eat, what makes you think that you are going to get 3 to eat??
Being patient is hard, but that is the only way you are going to get it right, you have had a damsel for 5 days and it is yet to eat, that to me indicates you are struggling, find alternative food, try feeding at different times of day, you need to learn a bit more before putting any more fish in the tank.
My first tank I had just a clown, and left it that way, the tank was about the same size as yours, after reading, I learnt that one small thing could happen in a tank that size and if you dont have a clue what you are doing, then chances are the fish are going to die as you are unable to figure out what to do to correct the problem. My first tank cycled for 3 weeks, but left it for 4 before putting a fish in, and i also did all my own testing, so by the end of the 4 weeks, i actually knew what it was i was testing and i could see the changes in the tank as things progressed and began to understand it more. Just remember to be patient, you arent going to get anywhere if you cannot be patient, adding more fish before you can handle 1 is not a smart move.