Depressed girl - should I move on?

Hello, I have been talking to a girl for about 7 months (we met on Tinder). In the first month the conversation was fine (even a little bit spicy). Then we were supposed to meet, but she canceled it like 5 times (too much work, sickness, etc.). I'm patient, so I did not care too much and waited until she had time. For the first date, we went to see a movie and to a restaurant, everything seemed fine. But then it started. She started to be more passive and the communication was very slow (2 - 5 messages per day).  She admitted she had depression, so I did some research online because I had no experience with mental sickness. I thought I would understand how she feels, but it left me just really confused. 

Since then, there has been no change in our relationship. We go for a walk or to eat somewhere like 3 times a month when she's in a good mood (but she only wants to meet outside). When she's happy she makes lots of plans, which get me excited too, but later she usually cancels everything because she feels down. Honestly, it makes me insane, but I am trying hard to understand how she feels and to be supportive.

My friends tell me I should move on but it seems impossible, I really like her. When we are together she looks like she likes me too (sometimes she gives me hugs and kisses, she introduced me to her friends when we met them, she compliments me, etc.). We have so much incommon, she's very sweet and caring and also insanely smart (which I really admire). But then she distances herself again and does not communicate. I feel really stuck and I do not know what to do. I tried to tell her how I felt but she changed the subject. She believes depression can't be cured, but promised to go to therapy (but I'm not sure if she really went there - I don't feel comfortable asking). 

I just don't know what to do! Should I wait until she lets me closer? Should I move on? In my delusional brain, I believe that it will eventually be good. Please give me some positive stories! 

PS. Sorry for chaotic writing and mistakes. I'm not a native English speaker.