I heard that a lot when I was younger, especially when I said I was too sick to go to school. The thermometer would come out: no fever, it's all in your mind. In other words, what I had just told them was made up, not real, not to be taken seriously. As I went back upstairs to get dressed for school, I shrugged it off until I was reminded of it an hour later at school. I had been feeling fine, and now I had a stomachache.
Power of the Mind
While the younger me preferred to believe that I was psychic, it was much simpler than that: where attention goes, energy flows. Our bodies make millions of processes and adjustments every single second of the day, some within our conscious awareness and some not. The fields of psychosomatic medicine and psychoneuroimmunology are devoted to the link between thoughts/emotions and the body. People regularly will themselves into getting better, or getting sicker, all with the power of the mind. An athlete in the final stretch of a major competition can severely injure himself and yet, decide to put all thoughts of pain from his mind until after the competition has ended.
Phobias can be one of the most debilitating crosses a person may have to bear, sometimes leading a person to build their life around that phobia, and what it doesn't allow them to do. Most of those phobias start with one moment, where something happened in the past and the mind keeps building and overlaying and intensifying the memory and its linked emotions. A simple event, a chance encounter, a single decision, all have the potential to hex a life for minutes to months, for days to decades. And it can be, on the other side of that, another different brief moment, perhaps not even what others might consider a significant one, that undoes years of pain and limitations, when the mind is properly motivated.
Looking at it All
Considering all of that, I say there needs to be a new interpretation of this phrase. When we say something is "all in your mind", why not focus on the all? Maybe we really have all the resources we need inside to face what life throws at us, and it just takes the right circumstance, or the right combination of factors, or the right guide to help us find them.
What is it that you have all of what you need already in your mind, that you aren't even aware of yet, and how will you go about discovering that today?