No worries, the next three years of doing your English Literature degree are going to be awesome- here's a list of books that might just help get you through:
1. Compact Oxford English Dictionary for Students (ISBN: 9780199296255): Trust me, you're not going to know half the words your lecturer says, but that's ok with a good dictionary you can soon swot up and get developing that pretentious self-conscious English Lit student vocabulary.
There are a ton of of dictionaries out there, but I favour this one as it tells you how to phonetically pronounce the words. I know some people thing dictionaries are obsolete because of spell checker etc. but dictionaries do give a lot better definitions.
The downside of dictionaries, is of course, that they're bloody enormous. You might want to consider investing in an electronic dictionary. They can be rather expensive, I have a Franklin Collins Paperback Dictionary/Thesaurus, which retails for around £48.00, although I got mine for free through my Disabled Student Allowance. The best thing about this electronic dictionary is its phonetic spell-correction, an absolute god send if you're dyslexic.
2. The Adventure of English, Melvyn Bragg (ISBN: 9780340829936): The English language is constantly evolving, just last week 'twerk' and 'selfie' were added to the dictionary. This highly enjoyable and accessible book takes you through the origins and developments of language. My favourite chapter is about dialect, as I speak with a pretty strong (and often mocked) regional accent.