Cat unexpectedly gave birth help!!

No emergency here we already took her to the vet got everything taken care of. She was only pregnant with one kitten and unfortunately it wasnt alive. We were completely unaware that she was even pregnant. This cat is normally the most aggressive mean cat ever. She normally hates people, doesnt let anyone touch her and she hisses when you look at her but now since she recently gave birth she has been 100% clung to me and my fiance. She sleeps on us and meows at us and the doctor said shes just going through the post partum stage right now. Theres definitely no more kittens as they did an xray. So when will her behavior return back to normal? Or will it ever? I love this behavior and id love for her to stay this way but im wondering typically how long they will act overly affectionate and clingy after birth? What should i expect now?