Anger, guilt, confusion, forgetfulness are common responses. You are not crazy, you are in mourning. Be aware you may feel appropriate anger at the person, at the world, at God, at yourself. It's okay to express it. You may feel guilty for what you think you did or did not do.
Guilt can turn into regret, through forgiveness.
Having suicidal thoughts is common. It does not mean that you will act on those thoughts. Remember to take one moment or one day at a time. Find a good listener with whom to share. Call someone if you need to talk.