How to make your suffering USEful:
Union. unite yourself to the suffering Christ through prayer, unite yourself through those suffering like you or more than you and offer your sufferings for them.
Service. serve those who suffer in a similar way. This suffering if carried in a healthy way will bring you to be more open to the emotional needs of others. You will understand what it means to be confused, afraid or in the verge of despair, and you will be able to provide the same support that you have received. If you are not able to serve others through active ministry you can always pray for people offering your sufferings. That is also service!
Evangelization. If you suffer patiently, lovingly and hand in hand with Christ you will be a sign of the power of Christ over pain and suffering. People will see how you carry your crown of thorns with patience, love and prayer and be inspired. Maybe later on the Lord will call you to share it as a testimony of his Mercy.
Do not despair my Sister! Do not feel defeated my Brother! Your suffering, with Christ, has meaning and is useful! If you choose to walk this this dark Valley with Him your suffering will have great meaning, just like His!