All imply the intention of getting into action in the future. I will states that it is something you want to do and will sometime in the future, such as "I will start meditating." It is on the to do list, and still not getting done. "I am meditating" infers commitment and present tense. I should and I need to implies judgment around something you are currently doing and want to change, again sometime in the future. Get out of the future and into the present. Notice the words you choose when you speak. Stop making declarations around what you want, need, will and should do. Stop talking about it and just do it so that you are in the "I am."