Niklaus Warner, 29, pleaded guilty to causing death by dangerous driving and causing serious injury by dangerous driving when he appeared at court.
The charges came after a two-vehicle collision around 5.15am on June 4, 2020, that resulted in the death of Meghan Pollentine – who was travelling in the same car as Warner.
Warner had been driving himself and his colleague Meghan back following the end of their night shift working as mental health carers and assisting with patient transport.
They had been travelling for around one hour and 15 minutes when the silver Ford Ka Warner was driving veered over onto the other side of the carriageway at Polegate, East Sussex, and crashed into an oncoming white Ford Transit van.
Emergency services rushed to attend but Meghan could not be saved and was pronounced dead at the scene.
The driver of the van suffered life-changing injuries and spent a month in hospital following the collision.
Warner was arrested and said he couldn’t recall the journey or why his car crossed into the opposing carriageway.
Officers investigating the collision viewed dash cam footage from the vehicle that had been travelling behind Warner’s car.
It showed the Ford Ka veering over the central white line on a number of occasions before the collision, and showed no braking had taken place in the moments immediately prior to the collision.
Warner, of School Road in Hastings, admitted both offences and was sentenced to three years’ imprisonment when he appeared at Lewes Crown court on August 20.
Investigating officer PC Doug Park said: "This was a tragic incident that could have been avoided had Niklaus Warner taken appropriate breaks in his journey.
"He had many opportunities to stop and rest, to ensure he wasn’t continuing a long journey while tired, but he chose not to take them. That choice has ultimately resulted in the death of a much-loved 22-year-old woman.
"Driving while tired poses a serious danger to yourself and all other road users, and it is not worth the risk."
After her death, it was found that Meghan, from Bexhill, was five months pregnant with a baby boy.
Paying tribute to her, her family said: "We lost our dear Meg a year ago in this very tragic accident. Meghan was passionate and happy go lucky, she had an infectious laugh and was overall a beautiful soul. Our lives will never be the same again after Meghan was so suddenly taken from us.
"There are some questions that will remain unanswered, questions that will always be there; why did he not pull over and rest when he had the chance to? Why did he not ask Meg to drive the last part of the journey home?
"I hope that Mr Warner uses this time to reflect on how his behaviour has impacted on our family and how we will never get to see Meghan again or meet her baby."