Grace Beech, from Ecclesfield, said she saw 'bodies and blood everywhere' she attempted to leave the concert.
The 27-year-old had been at the Ariana Grande concert with her 13-year-old sister, Eliza Phillips, from Chesterfield.
Grace, a mother-of-one, said: "We came down the stairs and turned left and that was it. Ten steps more and we would both have died.
"There were two massive bangs. There was a blinding white light and then it was really orange and red.
"The force was so strong that it flung me back.
"Eliza fell on the floor and I ended up falling backwards into the wall of the tunnel.
"There was all this smoke. I couldn't find Eliza for a few seconds, but it felt like a lifetime.
"I thought she was dead. She was on the floor, but she had dropped her phone and bent down to pick it up.
"Everywhere was covered with blood and there were dead bodies."
Grace said she grabbed her the hand of her sister, a pupil at St Mary's Catholic High School, in Chesterfield, and ran back into the venue.
"We just ran for our lives. We didn't know if there was going to be another explosion." she said.
"We were climbing over seats because behind us were all these dead bodies.
"People in the middle of the venue didn't know what was happening. They thought it was a speaker or one of the balloons from the show going off.
"I was screaming that there were dead bodies and we needed to get out. There was a massive stampede. We just wanted to get out alive."
Grace's mum Angie Phillips and brother Oliver Beech were waiting for the pair in a car outside the venue and witnessed the explosion.
"My mum and brother heard the bangs and my brother said that's an explosion or a bomb. They rang me and I was just screaming and crying down the phone," said Grace.
"When we got out I flung my arms around my mum and her legs went.
"I said to my brother that we need to leave and get out here because it's going to get gridlocked and there could be another explosion.
"I had blood splattered all over me and Eliza had blood on her jeans."
Grace said has been unable to sleep since the attack and isn't sure how it will impact her long-term.
She added: "I can't understand the people who have done this. Who would want to hurt innocent young people who were just starting out in life? There were kids involved.
"Eliza is a massive Ariana Grande - she loves her.
"All those kids had gone there to see their idol and they came out seeing this or were injured or killed.
"I will never be the same again. It was just like a horror movie."
See tomorrow's Star for five pages of Manchester Terror Attack coverage.