Translation:My sausage and my sandwich with sausage.
I would like to know why the first sausage is genitive and the second goes from acusative or nominative to instrumental? Its really giving me a "knot". Its like, the first one is "my" (specific) or "any" sausage in this world full of sausages :-) (but its моя - i mean: shouldnt be specific?). The second one, ok, its my specific sausage that combined "with" something turns from acusative or nominative to instrumental.