Well, I figured out the problem with my comments. Blogger thinks I'm a spammer, and is putting all of my comments in the spam folder. So, please, if you've gotten an email for a comment from me, check your spam folder to check and make sure it's not in there.
I'm not sure what to do- I've posted in the Blogger help forums, and been told it's not a problem with my account, that I should contact the individual blog owners to see why my comments aren't being appropriately recieved. But out of the few I've contacted, NONE of them moderate, and NONE of them have marked me as spam, so it is clearly Blogger doing it, and I have no idea how to get it fixed.
I understand that I comment a lot on a lot of different blogs- but I do this because I LIKE a lot of different blogs, and I know that I love getting comments, so I try to return the favor. I feel like Blogger is punishing me for being an active and engaged blog reader. I can post just fine, but I can't participate in any discussions. Grrrr.