It's sweet, but definitely nicknamey and affectionate. Anything ending with -ka and having a Slavic vibe seems overly familiar for use by the general populace. That said, I don't know that outside of Eastern
Europe people would pick up on the potential familiarity, and it's definitely fresher than
Michelle.
It makes me laugh a bit actually. My niece named her dolls Meeshka, Mooshka, and Moushka.
~Anna~