My DS1 was like this after the birth of ds2. He was 2 and became aggressive towards me. It lasted for quite a while and his behaviour was demanding in other ways. The birth of a sibling must be very difficult especially when you are used to having two adults to yourself.
This is hard to manage, but try and spend some special time on your own with her. Reassure her that she is very important to everyone in the family. Maybe let her 'help' with the new baby,by fetching things, singing to the babyetc. If she wants to, let her hold the baby(with support). It takes incredible patience to try and manage this kind of situation when you are sleep-deprived.
My DS at 7 is no longer aggressive towards me. He is very loving and caring, and is very fond of DS2(well some of the time anyway)