That was my understanding of the question. If you are asking what someone has been doing that day you would usually ask " What were you doing/did you do earlier?"
I agree that it sounds more natural; moreover, it is also a direct translation of 'wcześniej' (unlike 'before'). It will be the default answer now.
Robić is imperfective, so "did" is not a precise translation. "What were you doing earlier," works well though.
In the part of England where I live, 'what was you doing earlier' is used more commonly than using 'what were' - probably because it's slightly easier to say.