It is important to realise that although stress cannot be avoided, it can be managed. Prolonged periods of stress become harmful to the body and weaken your immune system to leave you depleted, feeling overwhelmed and prone to illness.
The office can be a place of stress for most workers. It is necessary to decompress and get away from the stress during busy work days. Make sure you get away from your desk at least a few minutes every hour. Go for a walk in the building or up and down a stairwell and breathe deeply while you are walking. Mindful breathing can increase your focus and lower your heart rate.
If possible leave the building and get out in the sun. Leave the "source of your problem" behind for a few minutes and go into the relaxation response. Close your eyes and breathe.
If your only option is to go to the bathroom or sit under your desk to get some solace, then do so. It's the result that counts.