Not sure what the problem is but your plant is showing bad signs of insufficient light. All of the pads should look like the bottom pad, nice and broadly oval. If you continue to grow it in low light, the branches will not be able to support themselves and it will droop over the sides of the pot. And you need to change the pot to one with drainage so you don't need to be so careful with the watering.

If it were my plant, I would break off the better shaped pads and reroot them and start the plant over again in strong sunlight. Your plant will never recover from the spindly pads it has developed.

Thanks! I assume I should I wait until the spring or summer to reroot and repot it? I'm surprised that it has been growing in insufficient light because I used to keep it in a room that was always very bright. I suppose it might just not be a suitable plant for where I live (Boston area) and will never get sufficient light, unless maybe if I plant it outside, but I'm not sure how well it would do with all the snow.