I found my old diary and now I'm scared

So I just found my diary that I got when I was probably 7 or 8. I'm not sure because I didn't start dating my passages until 2006 (there's a huge gap in between that first dated passage and the previous one though) But I did write in it for a period in 2006, 2008, two entries in 2010, and a passage daily for nearly three months in 2011 and not again since.

Now that I'm rereading through the passages, I realize that I was a much happier child than I am now. I worried about stupid things that kids worried about (and even said more than a few times that my siblings bothered me and I said I didn't want to talk or play with them ever again...which obviously failed if I'm still talking to them today)

But there is a part that does concern me from the entry of June 29th, 2006.

(Part of) the passage reads: I wish sometimes I would just disappear from this family. Even though it's the first time it appears in the diary, I remember thinking this for longer than that. And on the side of that part are little notes from 2008, 2010, and 2011 that confirm that I still feel that way (and if I knew where a sharpened pencil was I'd probably pencil in today's date and confirm it once again for future reference)

The passages from 2008 are really disturbing now that I look back on them. I wish death on myself quite a few times, state that my sister and some of my more stressful classmates (some of the passages I wrote during the last bit of 7th grade) are pure evil, wondering if the world has abandoned me, noting that I can't seem to do anything right, wishing for someone to be able to talk to that would actually understand me, and actually stating that I was depressed (which is scary, because I didn't think that I was seriously depressed until a little less than a year ago)

Then passages from 2011 stating that my life was stressful, and further proof of depression. And I can't help but relate to a lot of it even now.

There's a passage from May 7th, 2011 that reads: Today I'm feeling better than I did yesterday. I've been in a (relatively) good mood today, even though I'm not entirely happy. I'm a little upset over the fact that I never seem to do anything right, or the fact that no one acknowledges it when I do. Sometimes my feelings are messed up to the point that I don't even know how I'm feeling most of the time. So many things seem to irritate me, and sometimes I just can't help but get angry or frustrated. There are so many times when I wonder if someone is playing a cruel trick on me, or that the entire world is against me. After reading from my previous entries, I noticed that I've held basically the same feelings for years now. It's not really that much of a surprise, considering nothing really changes for good (causes, not permanent) for me. Sometimes it's really awkward living in this house, and I don't like it.

That passage...is disturbingly close to what I would write now in the diary. I actually have recently written something very similar to it somewhere (multiple places, I believe, but I can't exactly remember where right now)

I also confirmed in a later entry that our family is falling apart at the seams.

I'm actually not done rereading all the passages (there's about two months of passages left to read) but I get the general idea.

It seems that I was in a better mood if I wrote in it every day than when I didn't, so I might start writing in it again, just to start noting on some things I would never want to put on the internet or computer where my family could possibly find it (I realize that they could get my diary in their hands, but considering that I have forgotten about it multiple times, I'm sure that they've forgotten about it's existence completely)

So now what I'm wondering...is this enough proof to say "Yes, I know that I'm depressed."? Probably. I can't help but feel like I should be telling my mom, but like I told my online friend who is trying to help me, it's really hard to catch her in a time when she's not frustrated or in a bad mood. And I really don't know how to tell her.

I'm so scared, now more than ever. If I really started thinking these awful things in 2008 (I know there are some entries in 2006, but they're mostly what I expect a kid to complain about, not some of the more serious stuff from later entries) and that would count as the start of depression, then it would mean I've been dealing with it for more than 5 years now. It's pretty terrifying.

So, anyone that has actually taken the time to read this, do you have any suggestions? Because I could really use some help, now more than ever I think.