Your thyroid disease is common/not disabling, usually easily fixed with an inexpensive thyroid hormone pill Hashimoto's disease - MayoClinic.com (I am hypothyroid too). A learning disability might make things harder for you but is not totally "disabling", there are probably jobs you can do/have done so you would not be considered totally disabled. If you have not been working but have been getting income from somewhere else; they will expect you to keep getting that income; getting SSI doesn't happen suddenly, you have to show you really need it but if you are getting income from somewhere, you can't show that? If you are working, you'd have to show how the disability keeps you from making "enough" money to live on. Whether you think you can work or not is not part of the equation, just what your actual experience over time has shown. That you are in therapy or going to programs to teach you to work with your disability, that can work against you as it says you are "able" to get better, are not totally disabled and "helpless".

Disability Planner: How We Decide If You Are Disabled