I have struggled with masturbation as well. It is an emotional/hormonal release that works as a coping mechanism for other problems that aren't as easy to recognize. Loneliness, depression, idleness, fear of rejection, lack of faith, guilt, lack of self-esteem, etc. These feelings can sometimes be overwhelming and present a very personal, hidden struggle. The high you feel through masterbating then becomes addictive and it becomes harder and harder to resist the urge to seek that release.
From a biological perspective- your body is seeking a chemical balance. When things are out of whack, you will feel desires and urges for things that your body has already experienced and knows can (at least temporarily) restore that balance. The problem is that your body does not know or recognize the difference between things that provide temporary relief and what will be truly healing. You have to make that distinction for yourself.
If you are experiencing feelings of depression- speak with a doctor/therapist to find out if medication might be necessary. This isn't a fix, but it can help if you have clinical depression since this means that your body simply cannot naturally maintain the chemical balance it needs. And whether or not you need medication- these are all some good things that will help as well:
Exercise- getting your blood flowing and your heart pumping releases endorphins and improves your health.
Eat healthy- healthy foods also provide good chemical releases that are necessary for your body. You can talk with a nutritionist to find out specifically which foods might help you to determine whether or not you have any deficiencies in need of correction.
Get outside- sunlight provides vitamin D, which helps give you a "positive charge" and is why people seem more happy on sunny days as opposed to gloomy rainy days.
Keep busy- don't let yourself be idle. Ever. Idle hands lead to temptation. Fill your schedule with positive things to do like volunteer activites, college classes or talent workshops, hobbies, collections, etc.
Serve others- find ways to be "useful" and improve your sense of self-worth by putting your individual skills and talents to work helping others in need.
Avoid being alone as much as possible- spend time around other people as much as you can and get involved in activities that will get you out of your house and interacting with others.
Finally, we get to the spiritual side of things. It is good that you've contacted your bishop. He is going to be your "coach" to help see you through this rough patch of your life as you strive to overcome your weaknesses. When I saw my bishop, he had me keep a scripture journal- reading by topic on things like repentance, sin, forgiveness, temptation, etc. and taking down all my thoughts as to how these scriptures pertained to me. He also had me re-read the For the Strength of Youth pamphlet and write a more personalized version for myself.
Fill your time with spiritual things as much as you can. Whenever you feel a desire to masturbate returning, whenever an unclean thought enters your mind- grab your scriptures. Say a prayer. Sing a hymn. Do some pushups. Go for a run. Tackle it the moment it enters your thoughts so that it doesn't take root.
And last of all- keep a tally for yourself to help you see your progress. Don't just mark every time you give in. Mark every time you feel the temptation, and you resist it. And I can assure you, that as you keep a tally this way, you will see that you are doing better than you think. I went through a time when I would masturbate every day, and then maybe once a week, then about once a month. I would beat myself up every time and feel like a failure. But when I started keeping this tally, I realized that I wasn't failing. I was WINNING. And I eventually also noticed that I would feel that temptation less and less, until such thoughts hardly, if ever, even entered my mind.
Bhagavad Gita - “Man is made by his belief. As he believes, so he becomes.”
William Shakespeare - “This above all: to thine ownself be true, And it must follow, as the night the day, Thou canst not then be false to any man.”