Please help my sweet Luna get better

Our loving dog Luna started to show discomfort on her hind legs and lower back, as the days passed by, Luna started to limp as she walked.  We've taken her to the vet multiple times, done lots of x-rays, bloodwork, fecal exams, and ultrasounds and her vet found nothing abnormal.  The vet recommended pain medication that did not seem to work.  Soon after, Luna started to show blood in her stool.  The vet recommended we put her on strict diet and more medication.  It has been three weeks and we have seen no improvements.  Luna's vet referred us to a Neurologist who came to a similar conclusion that Luna is in pain but has no knowledge of what is causing it.  They highly recommend that Luna gets an MRI to help determine the root of the problem.  Unfortunately due to the COVID-19 pandemic and our expenses on her vet visitations, we don't have the resources to pay for the MRI exam.  The sooner we raise this money,  the sooner Luna will be relieved from her pain.  Luna is part of the family and seeing her in this kind of pain is unbearable to us.  Luna has been  our comfort in life.  We appreciate any kind of donation to help our Luna get better.