"I was" is usually correct, except when using the subjunctive. "You were" is correct.

To be grammatically correct the answer can only be I was you were he/she/it was we were they were you were going to English speaking countries you will hear sometimes " You was there " , which is only slang or as I call it lazyness .

You would never say I were, but you can say I was, you would never say you was (unless speaking in slang) you you can say you were.