As an American, well, we're about to be subject the the Chinese curse - "May you live in interesting times."
Trump will damage Democracy in America as much as he can during the next 4 years of his term. The checks against his abuse of power remain - The House, The Senate, The Supreme Court and State Governments.
Even though Republicans control all branches of federal government - there's been indication that some nominally loyal Republicans will balk at extreme abuse of power (likely to manifest mostly in the Senate and I think in SCOTUS).
State Government too will oppose Trump as best they can.
Is Trump going to end Democracy in America as we know it? Beats me. I think there's a strong possibility of that happening though.
What might happen in the worst case? Well, Trump might declare martial law to protect against illegal invasion by immigrants. He'd then begin to mass deport immigrants using the army. Having declared martial law, he'd then move to disband SCOTUS if they objected to him. The free press would have long since ceased to exist as Trump would move to void broadcast licenses for any entity he deemed unfaithful to his aims.
In short, American Democracy might end completely under Trump in the next 4 years. I'm not saying that this scenario is a forgone conclusion, or even that it's likely... it is though, very, very possible.
The bellwether for doomsday as outlined above is what happens to the free press. If Trump is able to silence the press through some means or another - then the USA is firmly on the path to fascist authoritarianism.