First, check your symptoms against a list of symptoms of depression.
Wikipedia's article on Clinical Depression is rather good. You list some of these symptoms: if you have five or so more, you should seek medical advice without delay.
Second, it sounds as if you are someone who drives yourself. This is good when you can keep things together, but it can screw things up when things don't go so well. Autogenic training is a well-tested technique that helps create some personal space, is easy to do, and it has good clinical results against exactly the symptoms you describe.
I hesitate to recommend materials in English, so I'm posting a story here:
Autogenic training: recommendations sought. Is your native language Spanish?