Losing a limb in a dream often symbolizes a loss of capability -- a skill, role, or sense of independence you're afraid is being taken from you. It can surface during a major life change, when you feel less equipped to handle what's ahead than you did before that change began.
The dominant star being in the Midheaven, exalted or in its domicile and taking part of the ascendant. - Picatrix (Andalusia, ~1000.AD)