[souffle]

She was spayed wasn't she? Sometimes an infection is deep seated inside and it just doesn't heal up I'm afraid. They are very delicate little creatures and their little bodies have little resource to fight off infections especially if they are already under the weather.
You have tried your hardest for her. It is nothing you have done or have not done and it is just nature that some will heal and some will not. The antibiotics will be affecting her ability to absorb food and get the goodness out it to heal herself but she needs them. It may be that the infection is not responsive to septrin? Baytril may work better? There are few antibiotics that can be used with hamsters and some that will kill them so the vet needs to be careful. It's a vicious circle. I'm sorry she is going through this and you the worry. I would give her whatever she will take just now. The infection may be in the vaginal area below the removed womb or the discharge may be from the healing tissue inside her. It's not easy to deal with and you can only do your best and go with your heart. She may tell you if she has had enough so listen for her whisper.
Hugs to you.