Depression Support Group
Depression is a real and debilitating condition that is often misunderstood by family and friends. Its meaning can range from a prolonged period of sadness to an actual mental illness with specific symptoms. Find and share experiences with others who are going through the same struggles.
http://www.nolo.com/legal-encyclopedia/how-much-does-social-security-disability-lawyer-cost.html
That link might help you out a bit, that's where I've gotten some of my information from.
The actual applying itself can be done online.
https://www.ssa.gov/planners/disability/dapply.html
That link should directs you to more information about applying and what information you will need in order to do so.
I hope helped at all. I know how stressful things like this can be. I've been applying and getting denied for about 5 years now, it's really depressing. Best of luck with your case if you decide to go through with it.