Kachalla Bukar's daughter, Aisha, who is 14, is among the missing.
He told CNN: "We can't get any information from the school because soldiers are all over there. No security came to Dapchi the day the men came, now over a hundred soldiers have taken over the village," Bukar said.
"I haven't slept for five minutes since the attack on Monday. I can't even eat or focus. The government should just produce our girls.
"Aisha has been sick for a while, I spent so much taking care of her before she went back to school. Now they are telling me she is missing," said the distraught father.
'Don't panic, we're not here for you'
Thirteen-year-old Hassanah Mohammed, who attended the Dapchi school, recounted the terrifying moment when gunmen wearing military uniforms burst into the school.
"We were about to start evening prayers when we heard gunshots outside the school. Everybody was terrified and we rushed to the gates and frantically scrambled to jump over the fence. I, my younger sister and two classmates managed to jump over the fence," she said.
"I had a sprint on my ankle but kept on running, holding the hand of my sister. We saw Boko Haram gunmen in military uniform and wearing turbans. They kept calling on students to come to them, that they were going to rescue them," Hassanah said.
"We did not listen to them and continued running. I was limping," she continued. "I lost grip of my sister's hand in the confusion. I managed to return home in the company of my two classmates but my sister has not been seen since then. I believe she was among the girls taken by the gunmen."
One of the parents also told CNN how he inadvertently witnessed his daughter being carted off in a truck along with the other schoolgirls on that fateful Monday night.
Adamu Alhaji-Deri said he was preparing for the Muslim sunset prayer at a mosque when he saw armed men in trucks shooting in the air.
The 42-year-old said the men ceased fire when they got to the mosque and asked residents to proceed with their prayers, Alhaji-Deri told CNN.
Alhaji-Deri said the men told him: "'Don't panic, we're not here for you. We won't harm you. Go ahead with your prayer inside your mosque.'"
As he returned from prayers, the militants later passed him as they drove out of the school with the schoolgirls in their vehicles.
"As they passed by me, I saw the girls. 'These are the schoolgirls,' I told myself," he said.
"My wife and I kept mentioning our 15-year-old daughter, Ummi. We were asking each other repeatedly if Ummi was among those girls that that were just taken away," he said.
He later heard that some of the girls were able to jump the fence of the school and run away, said Alhaji-Deri, adding that he hoped she had escaped.
"We've been living in anguish since we found out," he said.
'National disaster'
Nigeria's President Muhammadu Buhari has apologized, calling the incident a "national disaster" and saying that troops and surveillance aircraft have been deployed to search the entire territory for the missing students.
Buhari promised the families of the missing girls that they'll be found and their attackers brought to justice.
"We are sorry that it happened; we share your pain. Let me assure that our gallant armed forces will locate and safely return all the missing girls," Buhari said in a Twitter statement.