Hi and welcome!
I don't think you sound like a whiner at all. Those are horrible things that happened to you over the past few years. Anyone would be extremely stressed and upset just like you if those things happened to them/us. And you're not even whining about them....just explaining how things spiraled down weight-wise.
OK...first, the best thing you can do to start is to keep returning to this site and reading and posting. I see so many who introduce themselves and then disappear...and I worry about what happened to them. This site can be priceless in terms of help, support, accountability, etc. It was a HUGE help for me and continues to be now in maintenance. So keep returning...every day, preferably.
And the good news is that you don't have a whole lot of weight to lose. I lost 60 lbs. in about 8-10 months....and you can lose 40 lbs. in much less time, I am sure. In a few months, you can be right where you want to be.
Losing the weight won't fix all our problems, of course. It reminds me of the joke where a guy asks his surgeon (after surgery), "will I be able to play the piano?" and the doctor says, "sure"....and the guy goes, "that's good because I've never learned how to play the piano".

If you couldn't play the piano before surgery, you won't magically be able to play it after surgery. And likewise, just because you lose weight doesn't mean all your problems will be solved and life will be perfect. (I see many teen girls who think this exact thing, unfortunately)
For me, being overweight (downright fat, actually) made any stressful event seem 10 times worse. And it absolutely ramped up the feelings of hopelessness. Hits to our self-esteem are NOT good when we are trying to deal with the stressful/unhappy events that can suddenly come at us from left field. And those things will continue to happen, fat OR thin....but it is, IMO, at least, MUCH easier to cope when you are feeling good about how you look (not to mention how much better you physically feel).
So that's my stellar piece of advice....for starting off. Don't go disappearing on us. Make a commitment to stay here for the duration.
deena