Partly, yes. The main difference is that Trump's approval rating was for most of his first year well below Obama's during his first year in office (2009) -- see Rasmussen. Trump then caught up to Obama earlier this year, and they are currently doing about equally well. You could frame it as a "midterm slump", but considering how low he was for much of 2017, where he is now is an improvement. So I think it's more that he's improved his standing a little thanks to some popular decisions (e.g. tax cut, maybe North Korea), but he's still not a popular president, outside of the Republican party.
He was popular enough to get elected, so he must of at least attracted some Democrats, and Independents, but I agree we as a country are very, very divided on party lines. Very few if any Progressive Democrats which make up most of the party "like" Trump. In fact they hate him even though things like Black Unemployment being at an all time low should make them at least think a bit.
Many Trump supporters, including myself, don't think of themselves as Republicans anymore.