It depends what you think constitutes "an essay". From what you say, it seems to mean all the reading *and* the final writing (and any noting and drafting stages in between).
It takes me a minimum of 2 days to write a normal literature essay - more normally I allow 4. Two or so for the primary text or texts (obviously if the book is unusually long or short that's different), and day for critical reading, further reading and thinking, and planning; a nice full day to write. The writing itself, for a standard 2000-3000wd essay, takes me anywhere between 3.5 and 9 hours (hence allowing a full day, if I can). If it's an essay on short texts (like in Practical Criticism) I'll allow no more than 4 hours to do all the reading and writing.
Requiring 2 weeks to complete a standard-length course essay is a bit odd, and isn't really sustainable (as you've obviously realised). There might be several reasons it's taking you too long, and there are lots of things you could look at to change the situation:
You might be a naturally slow reader (I certainly am!), and it might take you longer than helpful to take in both the words and their meanings/wider implications. Some people are remarkably quick at this. However, this is something we just have to learn to work around. (Though, if you're interested, there are several methods to speed up accurate reading - I've never felt the need to try them, but apparently they can be very effective).
You might be thinking you're doing a lot of work when actually you're not. A really effective working day is 7-8 hours. Lots of people say they've been working "all day" and actually only do 2 hours' worth of work. Look very carefully at how much time you're *really* spending working...you might find that with concentrated and honest effort you could get the 2 weeks down to 4 days.
Do you spend too much time reading critical material? This can take up a massive, and unnecessary, amount of time. Be selective, and have a time-limit for this kind of work. (As I said above, for a standard 4-day programme, I allow one day for critical stuff, at most; often it's just a few hours).
Is a massive amount of time spent making plans in an inefficient way? (Being 'perfect' in presentation, for example; or writing things out several times [handwritten notes then computer]).
Or is the bulk of the time spent actually writing and editing? In which case, you might need to brutally cut down the perfectionism (which really does waste a lot of time for minimum results, sometimes - and is a real problem for some people), or find ways to speed it up! You could try just splurging out your ideas into paragraphs (following a loose plan), and see what happens.
Basically, there are lots of places to waste time in the essay-writing process. What takes you most time? And are you *honestly* using your time efficiently? (That is, if you think you're reading for 4 hours, is it really only one after you factor in tea-making and toilet/email/TSR breaks?). If you can identify the most time-consuming part of it, you should find it easier to cut it down.
Good luck!