What can I do to replace this awful habit I've created?

Habits can't easily vanish straight away - we need to set ourselves small goals and make a slow progression instead of an immediate one. Therefore, try reducing frequency of this habit per week then per day and so on. Depending on the habit type, it's an interesting idea to replace the habit with something similar or something that makes you feel just as pleasured or happy as a result of the habit. Remember, it all takes time. Patience and determination is key! It will be difficult at first, however reducing the frequency more and more will help you get used to it and get used to the replacement also.

Bad habits interrupt your life and prevent you from accomplishing your goals. They jeopardize your health -- both mentally and physically. And they waste your time and energy. Most of your bad habits are caused by two things... stress and boredom. Everything from biting your nails to overspending on a shopping spree to drinking every weekend to wasting time on the Internet can be a simple response to stress and boredom. What are you going to do when Facebook is calling to you to procrastinate? (Example: Write one sentence for work.) Whatever it is and whatever you're dealing with, you need to have a plan for what you will do instead of your bad habit.