My guess is hormonal changes. With the abortion, the spaying, all the changes she's gone through, it's to be expected.
I, like L4H, have just had a cat spayed after weaning kittens. But I am a mean person. I had her in a large dog kennel because I knew she was going to be miserable/cranky. Also I wanted to protect her from the other kitties in the house. She was a "B" with my house kitty before she was fixed; always attacking her, so I knew to watch for it afterward.
I would give her a few days. Is there a room she can be in by herself to recoup without the other kitties around? My little lady really seemed to enjoy knowing no one could get to her. Maybe all she needs is to have a while to recover fully. You may need to do a slow reintroduce afterward but it may be worth it for your peace of mind in the meanwhile. Just my