The Cosmic Christ through the Master Jesus stated, "With patience ye shall possess your soul." What is important is that you work with where you are at in your capacity. Many students raise the bar too high, and when they fail to meet their expectations, dive into melancholy, defeatism and despair.
You have to work in a practical way in your level. If you have trouble with focus, work with concentration practices such as observing a candle or visualizing a work of art. As for the latter case, you should not utilize anything too intricate, but a simple image, statue or painting. You can even take time to merely focus on a dot on the wall, which is a Zen practice for developing concentration and overcoming discursive thought. Some of these concentration exercises are laid out in the Gnostic Meditation Course, which I would recommend you review.
Once you have developed concentration, you can begin to meditate effectively on the ego. The referenced course linked at the bottom of this page offers a progressive didactic for developing a meditation ethic, discipline and practice. You can work with this course and the practices it provides in order to train your mind. It is a very straightforward and accessible course, so long as you spend the time and effort in fulfilling its regiment consistently everyday.
As for matters of consumption, we should always try to ingest the most nutritious and healthy food. We should also abstain from taking intoxicants and drugs, since these disturb the waters of the mind and create chaos. From what I can determine from your post, it appears you've come to some strong realizations. Contemplate the damages that specific actions cause within your life. Once you are aware of the detrimental effects of certain substances and foods, you will not dare to indulge in them again.
What will help you in this process is reflecting on what it is you want from these studies. If you want to change, then do so. Do not vacillate. When you know if certain activities cause you harm, then do not retrogress. It is a matter of will. You can work with the Rune Dorn every morning when you wake up. This will help to establish Christ-will in your interior in order to overcome the obstacles of the mind. These are just some suggestions for you to consider as you reevaluate your situation.
Joyful in hope, suffering in tribulation, be thou constant in thy prayer.
Benedictis, qui venit in nomine Domini. Osanna in excelsis.
"Blessed is he who comes in the name of the Lord. Hosanna in the highest!"