When you feel trapped in your cubicle or your room, take a moment to step outside, even if it’s just the balcony. This will help ease your anxiety.
There’s no cure for a broken heart except time. Allow it to pass and gradually cover the wounds that were left behind.
You need to be the one to adjust to the new guy on your team. Teach him how you do things and the dynamics of the group so that he knows where to situate himself.
If you don’t take a break from thinking, you’ll soon short circuit your brain. Unwind!