Thanks everyone! I bought an LED multi spectrum grow light, and increased my lighting to 16 hours, and that did the trick. I also have been feeding my spatulata blood worms, and it seems to be helping.
I also bought another drosera prolifera (my first appeared dead), and the other two 'sisters' of Queensland. I watched some videos on caring for them and wasn't aware of how much moisture and humidity they like, and that they prefer a cooler environment. I have put these plants in plastic containers with a bit of ventilation above, and water below, but the pots aren't sitting in the water (produce containers work pretty well, and I used a plastic container with a screw top, upside down, for the taller plant, sitting on a bottle cap lid, with water beneath it and a few punctured ventilation holes above. I also used an LED multi spectrum grow light, and these plants aren't on the windowsill but instead in my kitchen ledge, which is cooler. They've been in this new environment for about a week and they are producing new foliage already, so I think they're gonna make it.