Trying to be as vague as possible so this doesn't out me, and have namechaged.
I moved in with my older cousin (40s) and her husband and her two children a few months ago to find a job in this city. I was finding it hard to find a job I liked in my hometown and came here as there are lots more opportunities. I'm in my early twenties and female. I'm close with my cousins, see them all regularly, and have a good relationship with them.
She's always been fine with me, and this behaviour has started in the last few months. If I sit next to her, she'll move away. If I come near her, she'll wander away. If she's doing something and I try to join in, she'll move the book/ipad away and say 'no you're not allowed to see' or 'you're not allowed to do this'. I react as though it doesn't matter, either ignoring those comments or saying 'ok' - so she doesn't see she's getting a reaction from me and do it more for attention.
Tonight her and her mum (my cousin) were on the sofa watching a film, I came and sat on the sofa next to her and she started saying she wanted to sit the other side of my cousin (i.e. away from me). She started crying and getting louder and louder, and my cousins husband was saying to my cousin 'why not let her change sides, you're upsetting her, come on'. My cousin knows about this recent behaviour and husband doesn't, and held firm and made her stay still, but I just left in the end as I couldn't stand that I was making everything so miserable.
It doesn't seem to be simple attention seeking, as she doesn't explicitly say 'I don't like you', she just seems to do these things just because she doesn't want to be around me.
I've been in sole charge of her every now and then, and have had to discipline her at times, as she can have tantrums. I'm not over strict but I do hold firm (following her parents' lead). I explain why, for example, she can't go running outside into the street by herself, and then tell her that she can come back into the main room and carry on playing when she's finished tantruming. (eg - 'it's too dangerous to run into the street. if you'd like to go outside, maybe we could all go later. I'm going back into the other room with your sister. When you've finished, come and finish drawing with us'. I don't shout and haven't done anything that would make her scared of me!
Is she struggling from me going from fun cousin to an authority figure who disciplines her? Even though it's not very often? Just feeling very rejected and would love some ideas about what this could be and how to resolve this. I know she's only 5 and children can just behave oddly sometimes, but it's like a switch has just flicked over night!!!
Any help gratefully received, and I'm sorry this is so long.. Thanks