Hello, Sky
She sounds like she has urinary incontinence (loss of bladder control). The nerves and muscles in the bladder must properly work together for normal urination. When the nerves or muscles become weakened or damage you get the incontinence. This is seen more often in older pets.
This is treatable with medication. Talk with your vet about it, and ask for a contrast dye test. This can evaluate for congenital abnormalities and bladder position. You see this more in dogs. It can also have neurological reasons.
The number one thing you see is wet spots where the pet was lying, dribbling pee with out being aware, wet coat around the hind legs, and low abdomen.
You may read more about it here. http://www.marvistavet.com/html/body_urinary_incontinence.html
Let me know if you need further help
Sincerely, XXXXX
Expert in cat behavior and health
Expert in cat medical and behavior issues.
Glad to hear you went to the vet.
This treatment is very typical and common. Nothing to worry about. The DES capsules will help increases the responsiveness to bladder and nerves.
The amoxicilin I am sure is just a precaution in the event there is an infection present. (not a big deal)
You did the right thing, and so did your vet.
Let me know if you have any other problems or questions.
Good luck,
Mick