I don't have autism but I have a mood disorder that's pretty debilitating even with pharmaceutical intervention. Though I can ape being "normal" with some level of success, it takes constant and careful vigilance, so I know exactly what you're going through.

FWIW, it gets easier with time, though I'll admit that underlying fear that you'll be exposed never completely goes away. Also, I think it's important to remember that "normal" as a benchmark has no consistency, so a slip-up here and there (or even more than that!) is rarely noticeable to anyone other than us. You're fine. You'll be fine. Don't worry so much.