WolfishMusings,
A. Other people don’t seem to have these doubts. They’re confident that they have fulfilled the mitzvos, and perhaps they have.
That doesn’t make sense. If I have confidence that I’m the president of the United States, I might actually be the president?
And besides that, just because you don’t see people having doubts doesn’t mean they don’t have them.
B. Even if the previous point is false and I am like every other Jew, so what? Does the fact that everyone else fails at a task magically make it okay for me to do so too?
The gemara says that even the least of the Jews are as full of mitzvos as a pomegranate is full of seeds.