Ok, so I don't really know how to phrase this, because I don't really understand what I'm observing. I'm getting fed up of DH saying he can feel/hear nothing though, or that he has no idea what I'm talking about!
It's this. You're sitting in a room with the door closed. Maybe the window is open, but it might be closed. Someone elsewhere in the house opens an internal or external door and you feel the change in pressure, it's like a palpable wave of changing pressure that comes through the house. The closed door sort of moves in and out as the door elsewhere is opened (I don't mean the closed door opens and closes but it moves slightly within the frame), and the 'wave of air pressure' can also be felt in the room. I think if a window is open it can be different. Sometimes I'll actually feel a change in my ears (a bit like being on a plane but much less so!) as this happens. I hear a corresponding creak in the window frame or patio doors (depending on which room I'm in) as the 'wave' hits them.
So am I mad? Oversensitive? Imagining things?? I do have house-related anxiety and I'm aware of this, and that it might exacerbate anything I'm observing. But it is definitely a Thing and I want to know - is this normal? Do most houses have this sort of change in internal pressure?
For information, we live in a not-well-maintained 20's semi, single brick skin construction 
, fairly damp external walls. We have trickle vents over the (horrible) UPVC windows and they are mostly open.