Coconut water, chicken broth (the canned kind is full of good sodium), jello and rice water (cook the rice in double the water and drink the thick starchy fluid...it helps to bind things in there...you can add either salt or sugar and cinnamon to it)...when you are feeling better you can eat the rice.
If you get dizzy (which you probably are anyway) up your sodium intake (try mixing a pinch of salt, a tsp of honey and a few drops of lemon juice in with a jug of water...it can be drunk the whole time...helps to fight off dehydration.
Stay warm, use a heating pad on your lower back and get some rest.
Sharon