Say sit ONCE. Expect one action from one command. She probably thinks sit sit sit sit sit is her command. NEVER say sit or any other command in anger or with raised voice.

Come should always be a game and get lots of good rewards. A lot of people "ruin" the come command by making their dog come then doing things the dog sees as punishment (like being taken inside when they were nejoying playing outside, or giving medicine, etc.)

Get her to a training class. Its not for her, but YOU. You sound like you need a lot of guidance and a trainer will help you tremendously. Well worth the money and time a hundred times over.