I'm so sorry you feel this way. It sounds really stressful and frustrating. I went through something similar. At one point I was so upset I did not leave my bed for a week and a half, and I barely ate.
I'm able to get through the day more and more often without having a total breakdown more often these days. What helped me was seeing a therapist who does something "cognitive behavioural therapy." She told me it's actually the only therapy that's scientifically proven to work - apparently it works even better if you're taking medication during the course of therapy as well. I'd strongly recommend seeing a therapist for CBT, because it changed my life. If you can't get to a therapist just yet, I have found that there are some good books on CBT as well. One of them is called "beat the blues before they beat you." You can get it cheap on amazon. It gives you practical ideas for understanding your depression and dealing with it. Another good one is "Mind Over Mood." Just remember, you haven't tried everything -- you just need to find the right combination of therapy for yourself.