Google Apply for Social Security Disability and look for the official goverment site. They have the forms there.
Make an appointment at your locial SSA office (there is a locator function on the site)
There will be a person who will help you put together your initial claim.
When you apply the doctors cannot refuse to fill out the paperwork for the SS administration. There is no opinion place on those papers. It is all fact baced. If the doctors want to give an opinion they can write and give you a letter if you request it. Friends and family will also get an oppurtunity to fill out paperwork to give their point of view.
The SSA office collects records as far back as you have been recieving treatment.
They will look at all your work history (including whatever happened at these other jobs)
After the initial claim, (nearly all bipolar are turned down at least once. It is an "invisable disability" and you have to be like, missing your limbs, to get apporved the first time arround) go get a lawyer who does disability cases. They do all the paperwork for you, make sure all the deadlines are met and collect all the medical records for you. (I wish I had gotten mine sooner in the process)
I worred about the cost of the lawyer, but I found out the ones that are good at this take a portion of back payment of awards only. (mine will take a quarter of the backpayment, or $6,000, whichever comes first.) If they don't think you can get it, they don't take you as a client. If you don't get SSDI, then they don't get paid. You pay nothing out of pocket.
I was turned down twice before the hearing, so don't let that get you down. It took 18 months, so be prepared to wait a long time. I'm still in a place where I don't really know my feelings about getting approved.