Hiya!
Disclaimer: I don't do either at university, but I do both Lit and Lang at A Level, so I'll try and help with what little experience I've got!
English Literature: many people say this is a harder A Level compared to Lang. This may be true for some, but not true for others, it's a preference thing. Lit is a lot more intense than Lang; last year we had to read 4 pieces of literature for the exam, but next year there's an extra 4 books on top of the first 4, plus coursework - ahh! The exams are focused on a question surrounding the whole text, and I found it quite constricting. Doing Lit at A Level, and then at university, means you'll be spending your time looking very in depth at a particular writer, a small section of a genre, or a time period. It's true that Lit is far more prestigious than Lang, but that's mainly because Linguistics is a young and emerging field compared to the study of literature.
The kinds of things we do in Lit lessons: read the set texts (Measure for Measure by Shakespeare, for example), pick out specific quotations ("blood, thou art blood"
, analyse those quotations ('blood could be to do with violence, or sex, or being human/mortal, or about lineage... but mainly about sex'
, look at the time period and the influences at the time ('Shakespeare chose to represent sexual repression through the character of Angelo because, at the time, the Puritannical movement was garnering support and they emphasised ideas of virtue through chastity'
, reading critical analyses of said text ('Coleridge says the comedy in the play is "horrible"'
, compare the text to other texts at the same time ('Webster writes about a similar situation in The Duchess of Malfi showing the corruption of religion and dangers of repression through the two Aragonian brothers...'
and, of course, essay writing.
English Language: lots of people ask me: "what's the point in doing both Lit and Lang? Aren't they both the same thing?" Ho-boy. What a question. Lang is much more about a deeper analysis of the words we say and why we say them, and the effect of those words. You'd enjoy Lang if you think more critically and like being exposed to a variety of English texts with all kinds of genres and modes: one day you could be doing a critical analysis of the opening section of DH Lawrence novel, the next you could be analysing Dave Cameron's stepping down speech, the next picking out what makes a televised charity appeal effective (I've done all 3 of those this year!).
What we do in Lang lessons: analyse texts such as - political speeches, novels throughout time, advertisements, leaflets and brochures, travel guides and travel writing, websites, poems etc. For coursework, we're doing an independent investigation into a part of language we're interested in; I'm looking at whether gender or emotion affects language use, my friend is looking at the way kids speak, another is looking at the history of the English language. We also do a piece of creative writing, which you've said you'd enjoy! At university level, Lang gets more intense and delves deeper into questions like: how do kids acquire language? where did the English language come from? how does media affect language (eg Twitter, Facebook, Tumblr)? what are dialects and what do they do?
From what you've said, Lang definitely seems like the best fit for you. Creative writing comes under the Lang umbrella (at least, at A Level!), and one part of Lang is sociolinguistics (sociology mixed with language stuff). Media plays a large role in discussions of language too, and if you came out of uni having written a dissertation on the effects of Tumblr on punctuation (which is a really interesting topic!), you'd be set for a career in Marketing or Media as they would highly value your critical understanding of the English language and the ways you can manipulate and use it.
I'm sorry this reply is so long, but I thought if I could help, I might as well give you all the details I've got! Feel free to message me for more info