Considering following sentences.
- Not sure if I look so retarded or people don't understand me.
- Not sure if I walk so fast or others walk too slow.
- Not sure if I'm doing something wrong or you are trying to fool me.
Is it formal? if no how does formal one look like?
Is it possible to use "that" instead of "if"? the difference?
When should I use this form? and is there any other way to say it?
Thanks in advance :)