How does depression affect dating?

I dont suffer from depression, but I started dating a girl awhile back that does. Everything was going fantastic. Went on a few dates, FaceTimed or talked all day every day and things were getting serious. Well one day she said she felt herself slipping into a dark hole so she started her meds back up. Said she was exhausted and could barely function as well. Shes mentioned her depression several times but I didnt really know how bad it was. Then out of nowhere she stopped responding to texts and has been completely absent from social media ever since. That was about 7 weeks ago. She still goes to classes, she went where I go to school. At first I was livid because I thought she used me but several things stood out as major signs of a depressive episode. And one of her classmates works with me and said she asked about me the other day. Ive just sent her a weekly text ever since but I have no idea what else to do. Anybody suffer from depression know if this is normal behavior? Ive read online its extremely common but can anything be done about it?