My husband and i both work full time, my sixteen month old is still prefers daddy instead for me, am i doing something wrong? what does mean?

Nothing: You are doing nothing wrong at all. This is a very common thing for children to prefer one parent over another. This will change at various times of their lives. You are still mommy, and will be forever. If baby wanted nothing to do with you if daddy was gone I may be worried. My granddaughter prefers her daddy over my daughter as well. But, she still likes her above grandpa!