Hello Lily13,
I really find it awful when someone decides to give someone else a diagnosis when they know nothing about it. For starters, multiple personality disorder isn't even called that anymore, it's called dissociative identity disorder. That disorder would take a lot for you to be properly diagnosed with that and very serious so please discount that person's remark unless they have tested you, given you therapy or are a trained mental health professional!
It does sound like there is something going on with you. You are away from home in a strange environment studying which is stressful. There should be a counseling service attached to your place of study. If you are having delusions and mood swings and you feel things are not quite right then that is an indication to seek help and support.
__________________
Pegasus
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“Everybody is a genius. But if you judge a fish by it's ability to climb a tree, it will live it's whole life believing that it is stupid.” - Albert Einstein