I'm doing the right thing for myself
I don't understand why you're doing this.
I think, it is the right thing for me
It's good that you know what's right for you. Go for it if you think it's the thing for you.
Are you being sarcastic or do you really think it is good for me?
No I wasn't being sarcastic. Go do the right thing. It will help you feel good and accomplished.