I'm off Lexapro (escitalopram) now for just over a week and the only side effect I experience is tiredness it's interfering with my day how long until this passes?

Not long. It depends on what dose you were taking, how long you were taking it, and what other medications you are taking. Try to stick to a regular schedule, get exercise, and you should be feeling better in the next 3-7 days.
Another week. Tiredness is a common symptom after stopping lexapro (escitalopram). It usually takes a few days to arise, and while certainly bothersome, goes away within one to two weeks. If you are still experiencing significant fatigue for more than two weeks total, you should ask your doctor.
May be related. Why did you stop were you instructed to do so the side effects may actually be discontinuation symptoms and perhaps you need to stay on that dose or at least consult your prescribing physician for advise.
Perhaps never. Depends. Though this fatigue could be a discontinuation side effect (depending on how abruptly you stopped the medication), but it could be a reemergence of the depression that the Lexapro (escitalopram) had been treating.