Grief in a dream usually reflects a loss you're actively processing, whether that's a person, a relationship, or a version of your life that's ended. The dream can be an unusually direct space for that processing to continue, letting you feel and let go of something at a pace your waking mind hasn't allowed yet.
The vertue of a Planet is in that House, whose beginning or cusp a Planet precedes by no greater space than five degrees. - William Lilly (1602.-1681.)