B) Oh okay, it doesn't make any difference to me.> to a stranger > you might sound cocky if your facial expression is not helping . I wouldn't want to elaborate further . I would just say , Oh , in that case , its okay .
B) I feel bad, too.. but you'd better suck it up,,> very informal . Don't use with strangers .Its an idiom /slang . Only use with close friends ; just in case , you get misinterpreted as an uncaring person say " your problem , you deal with it".
I would just say " Too bad . Well, that's life (for you)