losing Mom and Sister 5 months after my Mom

I lost my Mom on July 25,2010 and my Sister on Dec.26,2010. My Mom had just turn 78yrs.and my Sister was 55 yrs. It is so hard and i can't seem to let them go. People tell me i need to let them go so they can rest in Peace. We buried our Sister on Dec.31,2010.Our family is not the same everyone is scattered especially me, i keep to myself and have lost interest in everything. Please pray for us. Thank you.