The two ways that I usually go by to start these kind of babble journal-y posts are:
"I don't know what to say... I've been lazing around and forgetting the things that I wanted to babble blog about... Ugh..."
Or, "My next semester just started! Woot woot! Now that it just started, I feel up and around and optimistic to do my schoolwork and studies well. My plans are......."
Or a mix of two, really.