I have a water bottle for my rabbit.?

I have a pet store water bottle, we have given it timothy hay and rabbit food. the rabbit was doing fine for a couple of days then all of a sudden (earlier today) it stopped moving around, half closing its eyes and becoming very unsteady. I saw it drinking from the bottle last night so I know it knows how to use it. It won't drink on its own now. It's gone downhill very fast. Will it ingest the water in its lungs if I force water with a dropper? It will break my kids hearts if it dies.