Depression can take different forms, and exist to different degrees -
reactive depression - as the name suggests can be the result of a trauma and will respond to professional therapry, possibly in conjunction with medication
medical depression - can be brought on by low levels of a chemical called seratonin which the brain manuafctures - again it can be balanced with medication.
You need to talk to your GP and get advice and treatment, so hang on until then - there are loads of people on here who will comfort and support you from personal experience.
I was hospitalised nineteen years ago with a complete breakdown, I was in for three months, and had almost a year off work. It took a long time to get balanced with medication, but that only controls the symptoms, I still have to work hard for my good days, and live through my bad ones.
Take comfort from us - you will get past this, it will take time, but you will be a stronger and more self-sufficient person at the end of it.
Stay in touch.
A x