Just thought I'd chime in here on a night-light related issue. I had read somewhere once that sleeping with the lights on was supposed to increase fertility. I thought that was pretty weird.
My DH and I had trouble conceiving for some time and then I found a tiny little link from a newsletter to a blurb about melatonin affecting the menstrual cycle. Melatonin helps regulate the sleep cycle. When it's dark, people's bodies produce melatonin and it makes them sleepy. Well, I've always been a chronic insomniac and had been taking melatonin tablets to help me sleep.
Long story short, we had been charting and everything before with no success, but I conceived DD the cycle I stopped using the melatonin. So I definitely think there is a connection, but I don't know how a night light would effect cycle length. Might be interesting to research.
Stress from moving to a new environment could also affect your cycle. Mine tends to go long when I have been stressed out.