Well, Nutrafin is supposed to be get the cycle started, but there is a process to using it. Based on it being cloudy and what you've said so far, I'm skeptical the process is working. If so, you have an uncycled tank with fish and possibly some BB, but clearly not enough. The bacteria you want are autotrophic that double every 8-24 hours. The cloudy water sounds like bacterial bloom caused by heterotrophic bacteria. Those double quite rapidly when no other bacteria is consuming the food waste in the tank.
The bloom will stay until leftover food is gone. You need to carefully and lightly vacuum the substrate especially if you can see leftover food. Do this gently as some of the BB you have are on the substrate. Key thing is right now the wrong bacteria are eating and these 'wrong' ones will compete with the good ones you do want.
Then, you'll want to let the tank complete the cycle. Feeding the fish very very lightly a couple times a day will work (although adding ammonia directly will work too, but the fish can do that as long as they don't die.) You want to do readings and not let the ammonia get too high since you have fish. Also do a pH reading to see if the pH is low. Water changes I think are not needed at this point, but will be needed once it's cycled.
At some point you'll get lower ammonia readings, higher nitrite readings and no nitrate readings. When you see the nitrate readings start to register you will be in better shape.
