Hi!
Any healthy guinea pig gut should gurgle constantly when you put your ear to it. You should however not hear it from across a room. Squeaking when peeing or pooing is usually a symptom for problems with the urinary tract (peeing) and not the digestive tract (pooping).
Contact the vet again for an antibiotic if your guinea pig is making red pees; symptoms usually firm up over the course of 5-7 days. In this case it is likely a urinary tract infection (UTI) or a cystitis (bladder infection). An antibiotic - either a brand containing trimethoprim-sulfamethoxazole or in short SMZ-TMP (usually known as bactrim, sulfatrim or septrin) or one containing enroflaxacine (better known as baytril) - and some analgesic like metacam are the standard treatment for that. I have added the active substances in the advice so your vet can check more easily for the according brands available in Turkey; but either antibiotic is safe to give to guinea pigs.
In rarer cases, the symptoms can be caused by a bladder stone or sludge - that is what your vet should check for if the antibiotic is not doing the trick within a week or if your guinea pig is suddenly looking very ill.
Here is more information to take with you if need to see a vet and to check with them:
Urinary tract infections and cystitis:
Guinea Lynx :: UTI
Safe medications for guinea pigs:
Guinea Lynx :: Medications
Dangerous medications for guinea pigs:
Guinea Lynx :: Dangerous Medications (notably any penicillin based antibiotics)
Please take the time to add Turkey to location in your account details (you find them when you click on your username on the top). This makes your country appear with every post you make and allows us to tailor any advice that helps you get what you need from a vet not good with guinea pigs, including the correct medication.
Please keep any further questions and updates to this one specially monitored thread so we can keep all information together and help you best.
I hope that this helps you? Urinary tract and bladder infections are one of the most common guinea pig problems.