I fantasize way too much about the past, future, and about how my life would become beautiful if I didn’t think so much. I’m a doctor and preparing for a specialty which requires a lot of concentration. So, I fantasize about how I would succeed in a career, kriya practice, and relationships - if only my thinking would not take me away from the present. Is there anything Guruji has advised about this? I’m way too intellectual always living in the past or future.
It is very good that you are aware of how living in the past or future gets in the way of your success. Awareness is a necessary first step to be able to change. Success in any endeavor requires one-pointed concentration of thoughts and energy on the project before you. Concentration requires that we engage our will to direct the energy toward a goal. When our thoughts are scattered like leaves in the wind, we have relaxed our focus and allowed the mind to wander in subconscious desires or old history. This mental place feels familiar and comfortable even if we know it is not the right direction. Will power, which we need for concentration, is desire plus energy, directed toward a goal. Desire is a key here! Think about why you seek this professional training. For such a challenge you will need to direct a lot of energy toward this goal. You will need to put desire for success in this area quite high in your priorities.
I wonder if you may have a mental habit of entertaining competing desires and letting them get in the way of progressing in multiple areas of your life, including meditation. Habits can be broken in a day if you bring intense concentration and desire to change to the problem. Breaking this habit in even one area of your life will bring you tremendous power to achieve success.
Meditation is an excellent training ground for our powers of concentration. When you meditate, observe carefully where you place your attention. In the meditation techniques brought by Yogananda, which we follow here, concentration is at the point between the eyebrows, the spiritual eye. As we meditate we constantly bring our attention back to that point. There is no need to be judgmental about the fact that the mind wanders but be determined to notice and bring it back, every few seconds if necessary. The neural connections in our brain will change to support our determined effort to focus. Put your brain on a training schedule to improve concentration! Yogananda advised that we keep our focus at the spiritual eye not only during meditation but also during our daily activities. I suggest you start training your concentration in meditation, honing your mind to ignore competing desires, and see if it does not carry over to concentration on whatever task is before you throughout the day.
Many blessings to you in your career and your spiritual life.