The president was expected to attend this year's edition of the World Economic Forum Annual Meeting in Davos, Switzerland.
Indicating the severity of Zimbabwe's economic problems, South Africa confirmed that it turned down Mnangagwa's request for a loan of $1.2 billion recently.
The president announced his decision to return early on Twitter, saying his trip had been "highly productive" but that his "first priority is to get Zimbabwe calm, stable and working again".
Local rights groups say security forces, accused of night raids at beating suspected protesters in their homes, were on Sunday trying to track down people who have gone into hiding.
More than 600 people have been arrested for alleged public order offences, including at least four politicians from the opposition MDC party. The internet was blacked out for much of the day, until authorities began gradually lifting a ban that had disabled some electronic communications in the country since Tuesday.
"Nothing has changed after the fuel price increase", said one motorist in a queue who identified himself only as Sonny.
He will stand trial on more serious charges of subverting the government after encouraging Zimbabweans via social media to heed a strike call from unions.
But Mnangagwa has faced a year of troubles in which his administration failed to improve the collapsed economy, narrowly won a disputed election and violently put down anti-government protests.
Zimbabwe's high court has ordered the country's government to restore the internet in full, ruling that the security minister did not have the power to issue such a directive.
The lawyer for pastor Evan Mawarire, a rights activist, said he would seek bail at the High Court after being charged with subversion.
Access to the internet was intermittent throughout the week, but people found they were unable to use social media and the WhatsApp messaging platform, which has become a common way to share news.
Zimbabwe's current president, Emmerson Mnangagwa, took office after the military pushed out long-reigning dictator Robert Mugabe 14 months ago.
"We don't have verification of the exact number of people who were killed or injured, but there are Doctors' Associations that are putting numbers out there that more than 60 people were treated in hospitals for gunshot wounds", says United Nations human rights spokesperson Ravina Shamdasani. She said described the case against Mawarire as a "travesty of justice".