Hey
@billyj as long as you are aware that we are not doctors and that this advice is best received from a doctor, then I'm fine with giving my two cents.
You're positive it is your kidneys? The pain is binary, on either side of your spine? Is it painful when you urinate? What does your urine look like/smell like, is it normal, dark, light? Are you hydrating?
If you could answer some of these questions, that would be helpful. For now, make sure you are hydrating aggressively. This does not mean making yourself sick with fluids, it just means drinking more than you usually would.
If you have not been eating food, which I assume is the case here, you need to be aware that plain water is not adequate for rehydration. You need to be taking in electrolytes along with the water. If a person were eating normally, then water would be fine. If not, then you need to get these electrolytes into your body somehow. The easiest way is to make your own rehydration fluid.
- One litre of safe water.
- Half a small spoon of salt (3.5 gms).
- Four big spoons (or eight small spoons) of sugar (40 gms).
- Stir the salt and the sugar until they dissolve in the water.
This is essentially what gatorade is, a sweetened drink with a little sodium included. For now, focus on that and trying to eat some food.
Get back to us about your condition and whether it's improving. Either way, I would say the best bet is to get checked out.