[Jords]

It seems to me youre looking for reassurance about your actions because maybe unconsciously you feel guilty not including her when shes clearly not having a great time.

Pretty difficult situation but have you tried being honest with her and letting her know how you feel? Maybe she doesnt know het attitude is bring the atmosphere down. Try making a big plan including all 4 of you? Like going to a theme park or something where she cant just 'run off' because you have to queue. If youre all friends you should try hard to look out for each other, and if she carries on then sadly you might just have to forget about her until you return or at least tell her 'let us know when youre ready to meet up' so she takes some action and its not just the 3 of you.