Oh geez. Yes your platys are pregnant. If you wish to keep them, keep an eye out for a white spot on their butt (cloaca). Once that appears watch over the tank for the next 12-48 hours. If you don't wish to keep the fry, do what the lock man said and let nature take its course
To expand on my previous answer a bit, if you do wish to keep the fry, then think again.
Platys give birth to upwards of 30 (and most often MANY more than that) every 4-6 weeks. Even when they're not sharing a tank with a male, they can store sperm packets to generate further fry drops for around 6 months. This applies to each of your females.
I doesn't take long for the fry to reach sexual maturity, so let's say that in 6 months you've had 4 fry drops from each of 2 females x 30 fry in each drop. That's 240 fry, so around 120 females in that group.
In the next 6 months, that's 4 dry drops of 30 fry in 122 females. That's 14,640 fish even with my incredibly simplified maths. Your tank ain't big enough. You will struggle to give away platies, LFS almost certainly won't want them.