Excessive worrying and over-thinking are very common because our active minds like to focus on either those situations which have already happened or those which might happen - like an annoying television screen that can only replay or preview. Constantly reliving the past or rehearsing the future can prevent us from relaxing in the present.
It is important to distinguish between those factors you cannot control and those you can. If you have done everything possible to produce the best outcome then you can choose to surrender to whatever results come your way. 
Eckhart Tolle’s book ‘Practicing The Power of Now’ outlines some practical techniques to help quieten a busy mind. Don Migeul Ruiz’s ‘The Four Agreements’ also contains some simple and useful tips. You might also find it helpful to listen to a guided meditation just before going to bed.

Craig Harper