This is a very difficult question. Depression have various degrees. Is it 'just' a week (or more) feeling bad or really depressed.
Depression(s) is a disease, not just a mood to stay strong in. Depression makes you feel black, real black inside. A hole you can't understand and makes you feel like nothing. It paralyzes you and your life.

So when you feel down, really down is different than feeling depressed.

So my answer to your question is...... if you're feeling down ....
Seek help or do a course, for instance mindfulness or something else you like. Don't stop doing things you always liked.

When you're depressed...... definitely seek help !!