We got into some arguments the night before (tried not to argue/react much, but don't know how to handle these situations well yet), then we didn't talk all morning. She then got her mom to pick her up and just left.

Haven't talked to her for 4 days now. Not even a text. Today is the day we usually get together for the weekend.

How do I handle what's coming up? Do I wait for her to contact? She'll definitely ask why I didn't even contact her and not talk for 4 days. I was just going to say I don't like arguing and thought I'd give her some time to collect thoughts. If I just say I had a busy week I'll (as usual, possibly) get bombarded with questions and she'll say "you never tell me what you're up to" and act all distant because I'm vague.

Or should I contact her and act like nothing happened, or?

No clue what to do here, but I don't want to hard next, at least yet.