I [19M] think my gf [17F] is getting too comfortable with me

Well my girlfriends has always been pretty tsundere. Which is fine because I know like in the end she means the opposite when she's being mean to me. And I've always been like the type of person who kind of makes people laugh by being or acting like an idiot. So I'm kind of use to people being rude to me. But my girlfriend recently has been pretty brutal. Like I'll be talking about what I was doing since we last talked, of course I asked her what she was doing before too. But she'll just hit me with "I don't care". Is it me or is that really unsettling? Maybe I'm being too sensitive but it just kinda throws me off. Like I remember once I was like yeah I'm gonna go watch anime while we were in a call with multiple people and she just said "I really don't care". She's very nice and friendly to other people maybe this is just how she treats people when she's really comfortable with them. There has been times where I want to tell her if she could treat me nicer I guess but then she just randomly tells me "I love you" and it makes me thing it isn't worth getting into. I just don't really know how to go about it because if I say something like I don't like the way you're treating me I don't want her to like not be herself? I know that sounds weird, but like I don't want her to act differently just because I said so. I just don't really know how to handle it maybe someone else does.