The nice thing abut etsy is that as long as you fill your orders, it is OK if you put less effort into it when you are busy wit other things. You should be focused on finals right now, and getting a summer job. That's no being lazy, it's just having your priorities straight. When finals are over and you've found a job, then is the time to set aside some of your free time every day, or a few times a week, to make and list new items and promote your shop.