Is this your first turbo vehicle? If so, what you're seeing is on the left hand side of the gauge is vacuum, aka, wastegate. If you aren't on the gas, or imparting a load on the engine requiring boost, your wastegate will be open (anywhere from fully where the bar is fully to the left to almost closed where the bar is straight up). Once you start making boost, the wastegate will close and you will start making positive pressure aka boost.
You can be making 10psi boost with your foot on the gas, and the moment you let off, the wastegate is going to open and its going to go full vacuum. You definitely want it to work that way. Imagine having an air tunnel, and the only way out is an open door (intake) while a second door is shut (waste gate). If you slam that first door shut, that air HAS to go somewhere, so the second door opens to allow the system to dump that access air.
The boost pressure you're seeing is fine, I typically see 2-7psi during my normal drives. I only see 10psi or so at highway speed climbing a hill in 10th gear.