As stated above SSI is state disability you get it first when your pay (holiday,sick,regular,leave of absence)from your employer stops.I think mine lasted 4-6 months.Your employer should be able to help you.
SSD is the social security disability I applied for next and I qualified for right away and they back pay you to when the SSI stopped.
Medicare is a 2 year wait but you can get cobra through your work though it is a little expensive as you pay for your part and the companies part for the insurance.I paid more each month for my HMO but I had lower co payments.Now I pay less each month but higher/more co payments.Sometimes cobra insurance can be extended.
You can also look into other insurances,gap insurance(helps to pay things your insurance does not cover) and medi-cal if needed.
Most insurances that offer insurance for people with pre-existing health conditions are for people over 65 and not us.
Patient advocate foundation-1-800-532-5274
I have some phone numbers for lawyers too if you need them but if you have social worker at your hospital they should have them too.