Female mollies can carry sperm packets from a previous mating and can use them to fertilise eggs for several months. Since your molly was in a tank with males at the shop it is very likely she is pregnant and looks as though she is near to giving birth. Then you'll have more fry a month or so later, then more, then more for quite a few months to come.
Any male fry which make it to maturity will mate with this molly, Eggnor and any female fry in the same tank resulting in even more fry. But the clown loaches will hopefully keep the molly fry population down.