Oh man..........just relax!
I heard that some japanese are not very friendly with foreigners but this is the same as in every other country too. I'm used to it because in Germany racism is still a big problem...some stupid skinheads or Nazis think that just white people sould live here but this is of course bull shit...
You shouldn't listen...and they're just strong when they're in a group...a single person can't do anything...
In Japan there are people too which like it to talk with foreigners...the problem is most of the time just to speak english...but if you know japanese everyone will help you I'm sure..
I was afraid too because of the food. I hate every kind of fish and I don't eat animals like fish, pig, cow or chicken...I'm a vegetarian....a real vegetarian...but there are enough supermarkets where you can buy meatless and riceless food!!
So relax and when you're older you will enjoy visiting Japan!
Just visit Japan for the first time and you'll see!