You are not like an Italian. = You are not similar to Italian people.
You do not like Italian. = You do not like the Italian language/food.
You do not like Italians. = You do not like Italian people.
Many different possible sentences for the second part, depending on what you want to say:
You aren't happy.
You are not happy.
You don't like being happy.
You do not like being happy.
Don't you like being happy?
Do you not like being happy?
Aren't you happy?
Are you not happy?
Why don't you like being happy?
Why do you not like being happy?
Why aren't you happy?
Why are you not happy?
Why are you, like, not happy?
...and so on.