Sick Baby Molly?

So I've had my fish tank for about 6 months now, and my molly (who died about 3 weeks ago) had a lot of babies. There was one survivor and it's been fine til now. I noticed that it spent most of it's time just laying on the rock, barely moving. It breathes rapidly, and I feel like she's lost some of her color (more white around stomach area). Still eats and swims around sometimes, but spends a lot of time just laying down on the rock or the ground. 

The other day I had to do a 100% water change because i had some really weird algae going on that would ALWAYS come back. I know those 100% changes are bad, two of the fish died, but the rest seems fine. Yesterday I had to move my tank, and I took the little fish in the net and into a plastic bag with the other fish. Once I put it back into the tank I noticed that it's spine was all bent. Is that something that I did? I broke its spine?! 

I got a testing kit, and it said pH and alkalinity were very high, it said the ammonia level wasn't dangerous but stressful, the nitrate was dangerous, and the water hardness was very hard, chlorine was 0. I bought one of those bottles that add bacteria so the nitrite cycle will go faster, but I'm just worried about my molly. Curved spine, stressed and breathes fast and kinda loses color.. I saw it could be symptoms of fish TB, but I doubt it. Any ideas?

What do you mean ammonia was stressful? Any trace of ammonia can cause fish to die very slowly.

I had the ammonia test strips and there were 5 different colors and at first it was more the color labeled safe, but i did it again and it looked more like the color labeled "stress"