@Murk at the end of the day what is your problem ?
she went out with her friend but all the time kept in touch with you , telling you what she does and stuff like that . More or less it was her way of saying “ I am out , but thinking of you “
if she would just disappear and only hear from her in the morning , then yeah you would have an actual reason to be mad on her
you are over reacting at the moment and this will only destroy your relationship . Now she knows your weak spot and every time you will annoy her , she will go out with her friends and if she will do it enough time she will also cheat
the only way to deal with this would have been to be cool with it , and in the moment you felt that she is pushing the line to downgrade her to a fwb position
anything else is a woman behavior
well done , you played yourself