Need some dog advice please!

I have a Labrador, she's really old and well trained, but ever since I moved, she will take a pee or a poo in the lounge room... on the carpet 😕 I have no idea why she keeps doing this, because she's house trained. She even peed when I was looking at her. She use to bark when she wanted to go out at my old place and now she's just walking into that room to do her thing 😥 even when I leave an outside door open for her. 
Guess she's going to have to be an outside dog now, I have no idea what to do. She doesn't seem to know what she's doing, I don't know how to punish her, I just say no in a low voice, but she just wags her tail. 
What should I do??