I think its time my friend :(

Those symptoms sound very similar to when our dog had Lymphoma, the losing body weight, diarrhea, general lethargy, we scheduled at home euthanasia and 2 weeks later he started to limp around and fall down when walking. If you can take her to the vet and get her healed that is great but at a certain point you are only prolonging her suffering and delaying the inevitable.