If you are a male, then Joiwan is probably 載雲 (carrying cloud). The last character 雲 is gender-neutral and is a very popular Chinese name, as cloud is a symbol of freedom and nobility in the Chinese language. The middle character 載 is probably indicative of a "字輩" (naming cohort), when multiple families use the same Chinese character in their children's names to indicate the same cohort. Check to see if your cousins are also named Joi. In any case, I think 載 is a legitimate name in its own right.
If you are a female, then it is quite possible that Joi is a misspell of Choi. In that case, your name would more likely be 彩雲 (colourful cloud).
If you are a female, then it is quite possible that Joi is a misspell of Choi. In that case, your name would more likely be 彩雲 (colourful cloud).