Yes, that is true. They will request information from your doctor. If your doctor has stated that you can not work, then you are at an advantage. You may want to give your doc a heads up that you have applied for SSDI. There are several factors that SSDI looks at and one of them being your age. You are very young so that will be an issue. The other is that you can not do
"sedentary work". You may get a call from the SSDI office to set you up with an appointment with "their" doctor. Don't be afraid of that. Just be sure to follow through with what they want.

I filled out all the paperwork at home and sent it in to my local SSDI dept. Then when they received it, they called me to give me some information on what to expect if I were accepted or declined. You may get this phone call too.

In the mean time, I would check with your state to see if there is any immediate help you can get with your medical bills. I imagine this would be through Medicaid. It doesn't hurt to ask, and many states have short term help available.

Some time in the future you may feel better and want to return to work. SSDI has a program that allows you to go back to work for a trial period to see how it goes. I received disability at age 52 and I am bored staying at home!