Abby,
It sounds like it went a lot better this time.

Yes, it can be a big relief to be told that you do have depression and are not just being silly or feeling sorry for yourself. What books did he give you to read? There are lots of good ones, and they do help. The problem with self-help books is that people read them and think that's a great idea, but then they don't follow what is in the books. It only works if you do it, but just make sure you take action and it should work.
Did he say anything about therapy?
How soon do you leave for India, and how long will you be there? I agree that the trip might be just what you need, even if you feel like you don't really want to go. If I only had a nickel for all the times when I wanted to do something, but then thought maybe I didn't really want to or didn't have the energy, or worried that it might not be as good as I wanted it to be, so I stayed home ..... A trip to India isn't something that just happens to you, so you must have wanted to do this or you wouldn't have made the arrangements, right? If you don't go I think you'll regret it.
So, now it seems that telling your parents about your depression looks like the next step? Writing a note helped you with the doctor - maybe the same thing will help you talk to your parents too. And having your sister's support will be invaluable. You could also share those books with them and talk about it. I do hope that your parents will be supportive and help you get better.
If you need more resources, I'm sure we could name lots of books and websites. You can search the web too. There was a website I found a few weeks ago and posted here, but I lost my bookmarks when my computer crashed. Maybe someone can help us find it and bump it back up to the top for you.
You never need to apologize for being here or for anything you write. You remind me so much of me when I was your age, and I'm very glad that you came here, and so glad if we are able to help you in any way.
Wendy
<font color=green>"Loneliness does not come from having no people about one, but from being unable to communicate the things that seem important to oneself, or from holding certain views which others find inadmissible" Carl Jung</font color=green>
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“We should always pray for help, but we should always listen for inspiration and impression to proceed in ways different from those we may have thought of.”
– John H. Groberg