Ok, thank you for the additional information.
Strokes are not very common in dogs and even less so in young dogs such as this.
The head tilt and inability to walk correctly is often associated with a condition called vestibular disease. This is very commonly confused with a stroke by an owner as the problem develops so quickly. The most common cause of this condition especially in a young dog is a problem with the inner ear such as infection.
Here is additional information
Another possibility is a problem with a disc in the neck. This can cause all of the problems you are seeing and is a common problem in this breed. Constipation is also common with this condition if the problem is effecting the back legs as well as the dog has a hard time getting in the position to go.In most cases advanced imaging such as a MRI is need for proper diagnosis
Here is additional information.
Another thing that can effect the neck, ability to walk, cause loss of appetite and fever is Meningitis
I would read over the above information and discuss this information with your vet. I hope this has given you some additional options for what may be going on. Please reply back if you have additional questions or concerns