Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your situation, and wanted to help.
Again I do apologize that my colleagues could not aid you sooner. If you would still like assistance, can you tell me:
Has her vet ever diagnosed a mass on the spleen?
What treatments is she on? Which antibiotic?
Can she keep water down?
Are her gums nice and pink (not white/pale)? Moist or sticky?
If you press on her belly, does she have any tensing, tenderness, discomfort, or pain?
Could she have eaten anything she should not have (ie bones, toys, plants, chemicals, human meds, etc)?