5wks pregnant after a miscarriage 5mths ago, told my blood type is negative an will need a needle with my next pregnancy, why? should i be worried?'

Don't be worried: All women who have a negative blood type should get an injection of Rhogam around 28 weeks of gestation and anytime during the pregnancy that they have bleeding. If the baby has a positive blood type, your immune system may make antibodies against the baby's blood. Rhogam prevents this. Its not something to worry about if you are getting good pre-natal care. Best wishes!