I am sorry that your mentor left you. Did that person feel that you were relying too much on them and not enough on yourself? If that was the case then you have to give some thought to that and think about what YOU need to do for yourself in this situation that is causing you so much pain. What can YOU do to bring about a different outcome without relying on others? What have you learnt from your mentors? How have you built on your strengths and strengthened your weaknesses with their help? What have you accomplished with their support? How much better off are you today than you were before they came into your life?
If you can answer in an affirmative way then B”H, they have helped you and have given you some basic tools that you have to reach for to continue. If you can’t answer in a positive manner then they were not the right shelichim and you have to keep looking, don’t give up. You need to keep on searching for answers and looking for the right sheliach to empower you.
In addition, sometimes when you find that life is just too difficult and challenging, helping someone else in need gives one a feeling of accomplishment and fulfillment. It is “nice” to feel needed and appreciated no matter who the source is or where it is coming from. It makes a person feel involved and NOT invisible.
Hatzlocha