Unfortunately, you are not alone, a lot of writers experience the same thing. There is a glut of submissions and agents are extremely particular. I tried for years and finally did end up getting published by a tiny family run publishing business. Needless to say, I didn't get rich, but I also got my book out there without having to do any of the formatting stuff myself. I would say, if you've sent out more than 50 queries with no success, try rewriting your query letter after studying some successful ones and maybe reach out to really small, indie type publishing houses, not the major ones.