Help plz

My rabbit has started to pull out its fur in a bad way !
What ever she can reach she pulls out mostly the back bum area I don't know why this is ?

We have currently got a new rabbit which we intend to bond with her after she has been dressed 4 week from now but I don't know why she is doing this fear or anxiety here previous mate died so she has been in contact with rabbits before !

has she been speyed, could possibly be false pregnancy?

Yeah

She has been sprayed for over a year and she isn't nesting !

She is a holland lop with a thick coat

Going to get her to the vet in the next few days she is eating and drinking ok so I don't know

Could she be in pain? I would take her to the vet tomorrow if possible just in case it is pain.