Is sushi a good idea?

im trying to lose weight (around 25lbs) and have been very good about working out. i eat sugar free oatmeal for breakfast with some fresh fruit, turkey wrapped in lettuce with fat free mayo for lunch (so theres no bread aka carbs) and then usually have sushi for dinner. i LOVE sushi but my stepmother is concerned about how often i have it. i usually get the philly roll (raw tuna or salmon with cream cheese but i ask them to not put alot of cream cheese in it so it isnt as bad) the spicy tuna roll, the eel roll and a side of edamamae. my stepmom keeps sayin stuff about mercury in the raw fish and it will make me very sick, that the rice is fattening (but theres not a whole ton of rice in sushi anyway) and that sushi is bad for me...is there any validity to what she is saying? is there a website that i can look up the nutrition facts (calories, carbs etc) for different ingrediants that go into my sushi?by the way the resteraunt is very clean and up to code..thanks in advance :)