Ask them what they need from you to make them feel supported. Put down your phone, turn off the TV, and tune into what they're saying. If you have health insurance, you are encouraged to contact your insurer for a list of participating health care providers and facilities.
Starting a relationship while clinically depressed will almost certainly be more difficult than dating without depression, and no one can magically cure your symptoms. Liam started constantly second-guessing himself and his confidence started to dip. When they are depressed, being there for them is the best thing you can do for them.