Umm, @ your last sentence, if you don't want anyone to judge you but you feel the need to post, I suggest you getting yourself a blog.
& I had a difficult time understanding what you have just explained but let me try to rephrase this. Your "ex-BFF" is a liar... you think. So you guys argued about phones and their ability to take pictures because you wanted proof. Then ya'll just started vomiting names at each other. Now you are confused because you have to sit through that awkwardness in the bus (BEENNNTHEREOMG. hecka.awkward..).
Just sit normally and don't talk if you don't feel like it. If you don't wanna make up that's your choice, so just act like you're sitting next to a stranger, but that doesn't mean rudely ignore.
If you do wanna make up, apologize and let it go.