Depression is so painful and you sound like a great friend. I've been depressed as well and have had loved ones depressed, so I feel like I can relate to your situation.

It sounds like you are very supportive. I don't know how much else you can do. If she has been taking her meds several weeks and there is no improvement then I think you should encourage her to call her doctor and her therapist.

Is there a weekly depression support group in your area? Check with NAMI, DBSA (Google for contact info) meetup dot com, and your local classified ads are places to look. They are usually free and you could attend with her as a support person.

If she is isolating, I'd call and leave a brief, supportive message daily or every other day. You have provided her with crisis contact information and that is great. I'm guessing she lives alone.

Please don't forget to take care of yourself. That's very important and it's easy to put ourselves second with a loved one going through a hard time. It's OK to take a step back if this is overwhelming you, it really is.