Trying too hard

Please help me find myself, I am so lost. I meditate, I understand and accept the Karma theory. I am trying very hard to do good karmas, in thought and action but I am failing drastically. I fall every day, accept my faults and try to get up but the tests are getting harder and harder. It has been over 50 years when I consciously started walking on this journey to improve. I want to do everything but I will not pursue to the finish line. This is my story when it comes to writing, exercising or any other project in life.
The only thing I am good is to inspire people in believing in themselves and improving their health and life. There are many who say I have helped them in all walks of life. I see this and believe it. Why can’t I use this inspiration on myself? I have been looking for peace which I experience to the max after I meditate, or am in gratitude but as soon as there is another test in life I fail badly. I am tired and exhausted mentally and physically. I need to fix things before the journey ends otherwise I feel like a phony inside. Help, Please!!!!!