I've had a miscarriage at 8wks but my baby was 5wks. how long does it take for everything to pass naturally? should i be worried?

Depends: Usually, a miscarriage that early passes completely on its own without any need for intervention. It may take up to a month to completely evacuate. See a provider if you are concerned.

Miscarriage: Miscarriage is more common than people realize. Usually early on tissue passes without intervention. There is an increased risk for infection if the products of conception (what's left after miscarriage) do not pass within a period of time, usually a fair rule of thumb is to give it up to 2 weeks, but be seen sooner if any fever, discharge that is foul smelling and/or increased pain. Good luck!