Dipping my toes in the water or diving in head first?

I have been working on reading through the many articles for my literary review and as I am reading a couple of dissertations I find myself wondering, how do we differentiate between a class project and a dissertation? What I am working on seems almost monumental and at the same level of work as some of the dissertations and papers I am reading. Am I taking too macro a look at this or am I just over judging the work? I would assume a class paper should just be dipping my toes in the water of a topic to get a cursory look at a problem and a dissertation would be trying to take more of a granular view of things. At this point I am having a hard time differentiating the two and placing myself on that trajectory.

I have broken my research up into a couple of categories: facebook, sense of community, millennials and online communities. I think each of these categories will help give me a good handle on the existing research and a good starting point for me to take my research. I have found some valuable thoughts and ideas in what I have been reading and am looking forward to applying this to my research. The current reading has also lead me to find additional articles that I want to explore. At what point do I call it quits and feel comfortable moving forward? Or do you every feel comfortable and just have to draw the line at some point. I guess this is my cry for assistance and guidance as I feel like I am diving head first into a pool that I am not sure I am ready to swim in.