why is najma sad?

so now its almost confirmed that najma likes imran.but she also seemed upset about something.everytime there is a talk abiut her nikaah she gets disturbed.even tosay she was crying while staring at immi's name in her phoneook.what might be the reason?does she know that imran is getting married to someone?or is it that imran does not reciprocate her feelings?or maybe imran and she were together before imran's wedding was fixed with nikhat?rajni did say that the locket looked more than 2 months old.