Write a short narration of facts (past/present/future) to answer the question 'what have you been up to?'.
You can summarize what happened yesterday, then explain what you're doing today and what you're going to do later or tomorrow. This is what we do when we answer the question above. There are other shorter ways to do so, but it's good to know how to tell people what's going on in your life when they ask you this question. It sounds natural when you do so appropriately.
As an student, yesterday I studied during all the afternoon, today I studied all day since morning, but as soon as I get home tomorrow I'll travel to Buzios to enjoy the weeknd.