I am so sorry you are going through this. I don't want to alarm you even more...BUT this seems very scarey now and I do think you need to bring Yoshi to the VET ASAP.
This is very serious now...He is very small and could go down hill very fast. Please bring him to the Vet now.
This has got to be a virus and he needs to make sure he is getting fluids.
I know nothing about parvo, but I would be worried about it at this point
