This is due in part to the fact that it is so painful, the idea of it lasting for years is overwhelming-as if you had to anticipate tolerating a toothache for the next three years or so. If depression, suicidal thoughts, etc. persist for weeks or months, perhaps seeming to intensify, it's time to seek professional intervention. I always tell people that if they wonder whether or not they should seek help, do. There is no shame in getting professional psychological help. It's just a shame to not get all the resources you can for life's most difficult task.
Most people approach the task of grieving in the same way they approach life in general.
That is, those who are assertive, have a clear sense of their own self worth, know how to have solid relationships and have a healthy spirituality inevitably do better at grief work than those who are, say, more dependent and passive. I have, however, seen many people who emerge from dependency on others, etc. There finally is no other place for look for understanding and hope than within yourself. Discovering just how truly strong and resilient we really are is one of the great eye-openers of grief work. This is a place where healthy religious beliefs can help a great deal.