Actually about a 35% rating is what I'd expect. Only about 1/4 citizens voted for him, he was never that popular to begin with, it's mainly because he eeked out some votes in the Rust Belt that he won because of the way the electoral college is set up. He lost the popular vote by a large margin. And a lot of those voters in the Rust Belt said explicitly they would turn on him quickly if he didn't live up to the hype.
He's also promised a lot of bullshit, "we're going to win so much you're going to be tired of winning" for example, and he has so far been doing a lot of losing overall as reality has set in. His health care plan was crap and failed, he said he would defeat ISIS in a 100 days, more crap, he said he would be too busy fixing the country to go golfing -- he runs away every weekend to Florida to go golfing, something that costs the taxpayer a ton of money because the entire Secret Service needs to go with him for his golf breaks.
His proposed buget is a bunch of tax cuts for ultra rich people with programs for average joes like after school programs for kids being cut. He's sold out the internet to big corporations and lined his cabinet with wealthy elites.
His cabinet has been dogged by ties to Russia and several have already been booted with Bannon getting demoted yesterday.
Don't confuse everyone who voted for him as someone who really backed him either, a lot of people voted for him in a "aw, fuck it, lets see what happens" logic which isn't paying off.
Also a lot of the stuff people don't give a shit about ... the wall, most people honestly don't give a shit about that. Most Americans are ok with people who have been here who are not violent criminals with paying a fine and then having a pathway to legal citizenship. It's not going to change their life any and it's going to cost a ton of money which he claimed Mexico would pay for (which was more bullshit).
