Estar vs Sentir vs Sentirse

In the same exercise, I translated "he wouldn't have felt so afraid" as "no se habría sentido tan asustado" but again it was corrected as "no habría estado tan asustado" and "no habría sentido tanto miedo". In the explanation pages for sentir and sentirse, we are told that we should use adj/adv with sentirse because it is about how one feels and with sentir noun should be used because it is about what you feel. I preferred to use sentirse+adj. I am confused why the version I used not accepted.