I don't knoe whats wrong with me but i have changed since moving for uni why am i feeling like this? ?

i use to be a really bubbly person always laughing smilling and being really loud.. since ive moved out 4 uni everyone hear thinks am quiet but when i go back home am normal with a few people @ uni am myself but in my halls am usually hibernating but this is my own choice i like to stay on my own and do my own thing.. i don't care about what people say about me does this mean am cold i think am shy but i dont know whats rong but something is HEELPPP