I've been a struggler myself, and I know myself how hard it can be to convince yourself that you can move forward on with your day. At times it does seem like it will never go away, and as that may be true it doesn't mean you have to suffer intensively. What I mean by this is, even though the depression is there, there's ways to limit the feelings you have. As much as you probably didn't want to hear it, the pain itself can go down in order for you to feel more alive. With that said in order to truly feel better you have to want to get better. What I mean is you have to be the one to be motivated enough to speak about what is wrong. Even if you simply don't know what is bothering you, that is enough for a doctor or psychiatrist to get you the help you need. You can get people to help you, you just have to talk about it. There are people, you just have to find your area in a way to reach out to them.
It's okay if you can't describe your problems, because honestly you don't have to. You know the feelings you feel deep down, and sometimes it's easier to just describe that then the memories itself.
As for the eating problem you've come across, what is making you want to do this? This is specifically a question for yourself, and even though it can't make you stop, it could give you an idea of what your trying to cover up yourself. With that said keep in mind that there are ways to keep yourself full without filling up on the sweets. For one thing you can try to drink water, or flavoured if preferred. With that you will know that the water will fill you up in a healthier sense. Yet, before you do that you need to be able to want to do this.
As for the cutting you've progressed to do, keep in mind that doing the above for another issue can help you out as well. Yet, instead of focusing on what to do to make you full, focus on what you can do to get the anger out. Instead of taking the pain towards you, try to keep your hands occupied with something else in mind. There's a lot of strategies you can learn to do yet, two of them are either to wear a wristband around your arm, or doing something that involves physical activities.
Good Luck.