Take a few boxes of stuff you don’t use any more to the local charity. Many people could use it and by turning down your visual “noise”, it will help relieve your stress.
Start a gratitude journal and write down things you are grateful for regularly. This lifts your mood and makes you more aware of how blessed you are for simple pleasures. If any person shows you a kindness, make sure they know that they are appreciated by writing them a note or by telling them.