Depression skews so many thoughts and memories that it is possible they were supportive and you didn't believe it.
I had a similar situation with a friend that was there for me for a long time and then I somehow just convinced myself she didn't care and didn't talk to her for 3 weeks (felt like a lifetime) and she was reaching out and checking up on me, and now I see her at least once a week.
I'm not saying you're family wasn't there, I have no way of knowing what really happened. I'm just saying it is very possible to warp what is really happening in your mind with depression. Hope you can hang in there and figure this all out.