I still ask myself those questions during dark nights of the soul, and I've been rejected over a dozen times!
It's going to sound hokey, but if you read
The Writer's Book of Hope by Ralph Keyes, you read stories like how John Grisham was selling his books out of the trunk of his car and you feel like maybe your day just hasn't come yet.
I also have a dear friend who has been a series editor for a very successful series of nonfiction books and has published a couple of other books in his own right. Last year, he wrote what I think is his best and most important book ever. Guess what? It took him almost a year to find an agent and his agent still hasn't sold the book yet.
I guess I'm just trying to say that it sucks, but every published writer has been there, every
great writer has been there, and you being there now does not mean you won't be published or aren't great.
Feel better.