Moving house: my cat meows every night

So, I've just moved house for uni. I moved out of my mum's quiet flat where there were other pets, and now I'm in a flat on a busy main road with just my little cat. The thing is, she really doesn't seem to be settling into the new situation. During the day it's mostly fine, she's cuddly and I take her out on a lead in my little courtyard (since she's not settled in the flat yet, I'm terrified she won't come back or might get run over). But at night, she hardly sleeps at all and just meows constantly (before, she used to sleep with me almost the whole night). She gets all freaked out, trying to find a way to get out and meowing non-stop. I've tried to soothe her with loads of cuddles but she's just not having it (her tail flicks a lot like when she's playing, but as soon as she hears a noise, she seems really scared). I don't know what to do anymore – pheromone diffusers aren't really in my budget. Is it just that she needs time to adjust? Does she miss the other animals? Is it because she doesn't have free access to the outside? (We always had a window open before, but she hardly ever actually went out). If you have any advice, I'm all ears – the nights are feeling very long at the moment.