Is it a teenage problem or what?

Alright, this often happens. I live with my grandparents, they're about 75. Everytime I say no it's as if I'm saying a yes. EXAMPLE! they called me on the phone saying that they're coming to pick me up for dinner, I said no, I heated up some leftovers and was full. Andddddd they go, I'm picking you up right now. As you can see, they're really old, why the hell would I want them to come back home to pick me up when I'm full, then go out again. WHAT IS THE PURPOSE IN THIS??! Then they decided to eat at home too. My grandmother asked me whether she need to cook me some eggs, I said NO. then she asked again. Ok that totally drove me crazy, from the phone call to this. I said NO HOW MANY TIMES DO I HAVE TO SAY NO, NO MEANS NOOOOOO!! Then here Im now feel bad about it. I really just.. ASDFGHJKL. Maybe my exam preparation is driving me wild. Idk help me please