You won't be able to claim anything for yourself but you will with your ds. Unless you go see a doctor now.
Insurance companies require medical documents. They don't accept the guess work of a travel agent, or from a chat with a doctor that your son seen. You need to have been examined, paperwork filled out, a written record that a doctor seen you in a professional manner. You will receive receipts and paperwork for the work they did and your diagnosis. Insurance companies won't entertain you without these, sure anyone could just say they got ill from the hotel.
If you feel this is more than a stomach bug and is due to negligence of the hotel, you need to report this to your rep and the agent back home, I'd also infom the insurance company so that there is a record of this, try have a paper trail. You must report to hotel management too, your rep will but I'd do this also. If there is a break out of food poisoning, they will have a few cases, they won't tell you, but there will be reported cases.
You can get tested for food poisoning, a stool sample will be taken and tested. I would ensure that every test was done before leaving there, because once you get home, it's difficult to prove anything. You may need to borrow money but you will be able to claim it back. Check your policy for the cover on hospital, tests, etc hospitals are usually quite high if you took out a decent policy, I always go for the maximum, mainly because we travel to the USA and medical bills there are painful.
I've claimed for a few things, not food poisoning but were tested for it, we've claimed for infections, broken bones, injuries from seizures, etc insurance companies will do their utmost not to pay out, they'll find every loophole possible to not pay out, that's why it's important to have a record of EVERYTHING from the professionals. We always take out the best policy and pay the excess.
If the hotel are baring you from public places they need to sort what you need, speak with your rep, they should sort this for you, your dh may have to bring food and drinks, but they should be ensuring that you have enough loo rolls, towels etc