Roxi needs surgery

Hey guys, we really didn’t want it to come down to this but we’re in a tight spot. Our dog Roxi is very sick. I’m sitting at the vet... again... (4th time to be exact) with roxi. When we got roxi we adopted her from a shelter, she was 8 months old and a total sweetheart. After having her for 24hrs she began to get sick. We called the shelter and told them what was going on and they told her to bring her in right away. As soon as we got there they ran some tests to find out that roxi had parvo. Even the word is terrible. Once we found out we made sure we got her medicine and we fought for her life because even though it had only been a couple of days we fell in love with our girl. After a few weeks she got better, grew stronger, and we saw the spunky pup that we fell in love with again. Probably 2 months after that we found that roxi was feeling sick again. She had a temp of 105.2, was shaking, groaning in pain, and very lethargic. We brought her to the pet ER right away. They ran a blood test and found out that she had a low white blood cell count, we couldn’t figure out why. We ran tests to check for tick diseases and got nothing back, we were all stumped. So we did antibiotics, some pain meds, and fluids... again a few weeks later she was better again. A month after that and we were back in the same boat, we ran more blood tests and they all came out the same... a low white blood cell count. Now we’re here again... a month or so later and she’s worse with a 106.4 temp. The vets are thinking it could be something to do with her bone marrow but it’s a extremely expensive test/surgery. I’ve already maxed out my credit card and now my care credit card. I don’t know what else to do at this point to help our girl. Our goal is $2,000 hoping that will cover charges on here, her surgery, her medications, and the stay at the hospital. I hate asking but we need help. Thank you and have a great day.