It sure looks like a watering issue. You might be giving it too much, or it might be getting not enough. Either would cause the stems to droop like that.
Stick your finger down into the soil in the pot as far as you can. If it feels wet, you need to check the drainage, and maybe put it in a different pot with holes in the bottom. If it feels hard or dry, the root ball may have dried out too much, and solidified so that the water you are giving the plant just flows straight through. The answer here is to soak the whole root ball in water for a couple of hours to re-hydrate the potting soil.
Another way to find out about a watering problem is a little more messy - get a sheet or two of newspaper, lay the plant on its side on there and slip the pot off the root ball so you can get a look at it. Soggy, you need to let it dry out some and check that the pot is draining. Dry and solid, you will need to soak it.
