I agree, its very variable. I'm also new, been here about a month and half and still very much in the reading phase. I tend to set myself little tasks every day that I have to get done, like reading and making notes on one paper, downloading a couple more, a bit of data coding, a bit of teaching stuff. I keep the tasks small so I don't feel overwhelmed, but over the course of a week it adds up to quite a lot. I'd also say you can't really compare yourself to other students as everyone has different topics and work at different paces. So just relax and go at your own pace :-)