You over-did it. Your tank will soon be overcrowded and some of the individuals you have are incompatible. The people at Petsmart are there to sell you fish and chemicals, not to advise you about proper husbandry. Most of them probably have little or no experience. I agree that if you keep buying fish there without using QT your tank will not be overpopulated for long as you will inevitably introduce disease.
Unless you want to split these fish at least 3 ways in equal or bigger tanks than you have now, I'd say it's time to reassess and regroup (and make some returns) Decide which species is your favorite and build around it with compatible fish rather than going to the "Petsmart fish buffet" and feeding that addiction!