You do not need a degree in anything to be a games 'journalist'. You need to write some pieces that get published (pretty easy given the internet) and build up enough work to be able to show somewhere that are willing to offer you some money for a few pieces then go on from there.Which is all very simple, apart from the important thing you forgot - you also need a recognition that there are literally thousands of other people doing exactly the same thing as you, and only a few dozen paid jobs waiting at the end of it.
One thing that hasn't really been asked here, as far as I can see, is whether this is just one unit you're struggling with. Are you doing fine with the assignments for your other units, and if so, is this a core unit? If it's just a unit you made a bad choice on, then there's a strong argument for just doing your best and making better unit choices in future. If it's a core unit... Well, yeah, you should be thinking about whether you can change your degree, as a second year essay in a core unit is NOT something you should be struggling this much with.