26wks pregnant! Can barely breathe. 😓

Soo idk if I’m just being a hypochondriac or if this is normal but starting over over this weekend.. I feel like it has been harder to breathe. When I sit in a

normal position and when I lay down .. it almost feels like my lungs aren’t expanding enough. But if I stand up and walk , I feel much better. Just having trouble breathing is freaking me out. Taking a deep breath doesn’t fix it at all. Anyone else experience this during pregnancy?