Cut her some slack guys. Yes shes cringe and at least to us pretty stupid but look at what shes gone through. She has her head bashed in, dies and wakes up 3 years in the past. That alone would probably cause the mental stability of anyone to crumble.
Plus compare the swings her daily life took. One day youre living life full of friends and a bf/gf and next thing you know youre eating lunch by yourself behind a dumpster. Thats a pretty big shock to someone who seems to have had it all.
Besides real life logic doesnt mean sht in manga. All this is happening to drive her upcoming arc.