Grief is one of the most devastating emotions. If not managed properly, it can lead to terrible consequences. So how do you manage it?
1). Like with any problem, run to God for help. You may be experiencing bitterness toward God for taking away a special person from you. But understand that it is not God who created suffering. Death came as a result of sin. And God is the only power that has power over death. He is the only power who can heal you from consequences of death. Cry out to God to help you overcome grief. God can help you overcome any problem. But you need to make a decision to surrender to Him, so He could help you and comfort you.
2). It is ok to cry. It is ok to feel down. Just like in an economy, there are times of depression to allow for a rebound to new heights, so it is in our lives. A depression, a state of beign when you don't feel like doing anything, is a natural emotional safety mechanism to help you overcome stress.
3). Don't go at it alone. You would tend to isolate yourself and want to cope with the suffering out of everyone's sight when you are experiencing grief, but resist this urge. Do the opposite of what you feel like doing. Surround yourself with people. Schedule a visit with a pastor. Call your friends. Visit church gatherings such as small groups. Just talking to people will help to keep your mind away from your problem.
4). Find somebody to help. The best remedy to cope with your own sufferings is to find somebody else to help. Join a volunteer group, find a person in need. Helping others will help you feel better.
5). Allow God to help you to see a future. You may feel nobody can replace the person you lost. But in God's kingdom, there are billions of people. Don't allow the past to prevent you from having a future. There are a lot of people who have stopped living while still alive because of a devastating loss, when God and people around them try to desparately give them a future and a hope.