Hi Jia. I am so sorry to hear about your Luna. Pippin went (and us) through a very tough time. It cost us a lot of money and effort for us to get her to where she is today. She was diagnosed after she turned a year old. She was on steroids for a whole year. She could not walk for at least 8 weeks and we had to carry her onto a pee pad each time for her to do her business.
She also put on a lot of weight(34lbs) due to steroids and other meds. It took her about 2 years to really recover. She is now 25 pounds and is back to normal. Although I think the meningitis took a lot out of her, sometimes I think she is not as smart as she use to be. She is now 4 years old. We now have Gimli our second corgi who is 2 years old, (who also happen to be her nephew) that keeps her company.
Once they fight off the meningitis, you have to be careful that it does not relapse. That's a nightmare and it won't be pretty the 2nd time around.

Good luck and stay strong.