I feel like, if Hillary was elected it would around the same approval rating, however this is terrible for trump.
I agree that she too would be unpopular. It probably would be a bit higher than Trump's rating, her favorability was higher than his (not by much) and she might make some effort to reach out to those who didn't vote for her. I think both Trump and Clinton were likely one-term Presidents. On one hand, I don't want to bet against Trump, but on the other hand the evidence points to him being a one-termer.