I'm a Russian book that inspired a year,
We - a dystopian novel by Russian writer Yevgeny Zamyatin which inspired George Orwell's 1984.
And used by the Queen in everyday speech.
The 'royal we' which monarchs use instead of 'I'.
Doubled, I'm small in the land of the north,
Wee - doubling the 'e' means small in Scotland & N. Ireland.
And then may be also found in the loo.
Wee meaning pee.
Just in time, I'm half of seven;
The seven of time may be week, which 'we' is half of.
Fun when that seven has ended.
If the same seven, the weekend is often a fun time.
Two letters, but either may be doubled;
W is double-u, and e is doubled in above clues.
Am I using the wrong word all along?
May refer to you using 'I' for one word, though we/e are two.