Feed just once a day for the moment, you are doing what is known as a "fish in cycle".
You will need to do a 50% water change probably everyday also, the fish are excreting ammonia and the fish poo and uneaten food is rotting to produce more ammonia. I suspect most of the symptoms are because of that ammonia. As the tank ages and the plants grow it will start dealing with ammonia and the water changes can be weekly.
The cloudiness might be caused by too much rotting food and fish poo, the cloud is heterotrophic bacteria eating the organic molecules in the water. These bacteria are increasing the oxygen requirement of the system. You have probably done the right thing by adding an airstone and doing partial water changes to dilute the ammonia and organics.
I suggest you have a look at
https://www.fishforums.net/threads/cycle-your-tank-a-complete-guide-for-beginners.475055/ , and maybe some of the other posts in the "cycling" sub forum, and then you will understand why you want to know the numbers a test kit will tell you.
For some of us weirdoes testing is part of the fun, but it's only really helpful in situations such as yours and when doing a "fish-less cycle" to be honest.