What you are experiencing is a totally understandable reaction. It's something many of us deal with: Namely, you've lived your entire life in a world that says that being different is bad, wrong, inferior; that disability is a tragedy; that you need to be "normal" or you can't have a good life. However much you know rationally that those things aren't true (and they are NOT true, trust me on this one!), being exposed to them your whole life will imprint them on your brain until they become automatic, and you're not even aware that you're thinking them anymore.
What you have to do when your brain starts playing those recordings of you being not good enough, not normal, not acceptable, is to look at them straight on and challenge them. When your brain says, "I'm a horrible person for not crying at a funeral," you come back and say, "Why? What's horrible about it? Who says? Why am I listening to them?" Often times you will find there's very little rationality about those ideas, just a lot of people who believe them. Well, a lot of people believed slavery was okay and women were inferior; they were wrong, too. Just as wrong as the people who now believe that autistics aren't as good as "normal" people.
You're going to take a long time to erase those recordings. I'm still working on it. But you can. I know, because I've made a good deal of progress. Use your logic; question everything. Read about other people with disabilities who've figured out this stuff. Get some perspectives on your life that don't come from people who worship the normal. And don't sell yourself short. You have as much right to be on this planet as the most normal, average person in existence.