Songbird,
So sorry to hear about your miscarriage and for how you have been feeling.
As for SSDI, the process really seems to vary from person to person. Some breeze through and others get denied and have to use the appeals process to get what they have rightfully coming to them. I was approved on my initial application; it went relatively quickly. But you really need to know what you're doing and my personal opinion is that unless you are very obviously disabled, legal representation is a very good idea.
There is a special Neurotalk forum for Social Security Disability I'd start browsing through it; there will be a lot of helpful information in there. Good luck to you!
http://neurotalk.psychcentral.com/forum28.html