What should happen is you should find a body on the ground, interact with it with spacebar, then you should get an indicator that you have retrieved item "pills" after that the scene should fade to black and you should exit the white room and end up on that level again, at that point you can open your bag with "B" and use the pills which will trigger the next event.
Hi and no worries! I'm happy to have the opportunity to interact! Are you able to open your bag by pressing the "B" button? The invisible wall is intentional, the way it's supposed to work is that you open your bag, select "pills" and then select "use pills" which will cause some creepy stuff to happen and then open the next area. Let me know if that doesn't work :)