Either something has happened that you dont know about or this whole process is catching up to her and taking a toll on her health.
I would continue to try and bring her out of her shell. If she doesnt want to go to a party, bring the party to her sometimes. Sooner or later, she will come back but it will take work from your part as her friend. Dont let her go.
Maybe a counselor can meet her in a more casual manner? Do you think its possible for someone to see her in a non-office type setting so she feels comfortable talking?
Do you know of any eligible men you could introduce her to? Also, sometimes the rishta process is easier for some and not so easy for some. I barely ever got upset if someone didnt call back. Some people though, really take it to heart. Maybe her mom can try to make sure there is interest before bringing these guys home?