Every day, make sure you give your best effort. Doing this each day is the only way you can improve and feel that you are growing. It is the same way when you train. Everyone has a different schedule. However, your determination is important.
Some people have more time and can come twice a week, three times a week.
No, that's your perogative to decide how much time you really spend on training. You should not carry your problems onto the dojo floor. As soon as you stand on this floor and put on your gi, you shouldn't think about any of your problems. As soon as you put on your gi and tie your belt, that's your time. You will forget your problems.