I'm so sorry, I lost one the day before his 4th birthday due to wobblers, I'd love to say it gets easier, it's 3 years later and I still think of him almost daily, I think it's the constant thought of what could have been. I take my comfort from knowing even though his life was short it was a very happy one and he was deeply loved.
I am so sorry to hear your devastating update, it is so unfair when they are young and you have such hopes for the future dashed by such an awful disease.