Social mistake

Introduction:

Hi I posted on here a couple of years ago and it helped so I’m doing it again.

Context:

Im at uni now and doing well. I have made a group of friends and they’re lovely. Today we went for a meal (not much planning went into it, hadn’t been there before and it was a loud place - but that’s okay).

Event:

So it’s the end of the meal and we are all paying for the bill and I am the last to pay. The waitress hands me the card machine and I go “wait are we giving a tip?”. They all go quiet and look at each other. In hindsight I should have realised at this point but I continued to ask. Because surely if we do we need to add one now here otherwise it will be too late (I assume we don’t have cash because they had to get cash out the other day for something else). Anyway I paid and the waiter left. Then they all turn around at me and start shouting (now they weren’t actually shouting shouting but it was louder than their normal voice and it was unexpected and I didn’t have my headphones on. They start telling me I can’t say that it’s rude and that this is her job and it’s wrong and that I shouldn’t have said that and that if they were the waiter they would have spat in my food. 

I was so confused. It just came from nowhere. Everything was fine a couple of seconds ago. Im now just hiding in the bathroom because I’m just well I actually don’t know what I am right now. 

Can someone tell me their thoughts? Am I being dramatic, are they? They all know I’m autistic but I don’t think they actually know what it means, not really, or what it is like.