My journals are like this, full of entries that apologize for their intermittentness. I've mostly made peace with my journaling habits (intermittent, yes, but still a bit prolific--but besides, I'm writing them mostly for myself anyway) but blogging is a little different. Nothing to prompt self-expression like a consistent audience.
And something about the discipline of it is really helpful. I would like to be a writer; Stephanie Meyer, no; Richard Dawkins, no; I don't care that much about making money or reaching a wide audience, and there are very few mainstream modern writers whose work I appreciate. What I would like is to make something that I think is really good, that in some sense fulfills whatever talent I have, and to share it with a handful of people who find it precious.
And for that, I need practice--practice writing for someone else. Practice writing for you.