Paramedics took 31-year-old Tristianna Mahana to Bassetlaw District Hospital on Friday July 10 after she'd been found in Worksop but her condition deteriorated and she died in hospital two days later.
Detectives are not treating her death as suspicious.
Tristianna left her supported accommodation in Ollerton at around 9am on Thursday July 9. She attended Bassetlaw District Hospital later that day, at around 5pm, before leaving around 20 minutes later. She wasn't seen again until 5am the next day when she was spotted in Worksop, near to the Celtic Point Retail Park.
Tristianna was last seen wearing a grey beanie hat, cream puffa jacket, red pattern leggings and dark pink trainers.
Detective Constable Hannah Newbold, from Nottinghamshire Police, said: "We are appealing to anyone who saw Tristianna or came into contact with her in the Worksop area, particularly at Celtic Point or Bassetlaw General Hospital, between 9.30am on Thursday July 9 and 1pm on Friday July 10, to please get in touch.
"We are working hard and our enquiries are ongoing to piece together her movements leading up to her death, to establish what happened to her and what might have contributed to her death. Even the smallest bit of information might be useful to our investigation.
"We know that she spoke to people around the Celtic Point shopping centre and we're trying to trace them including someone who spoke to her in the car park area.
“She may have seemed like she was intoxicated when people interacted with her.
"Tristianna's whereabouts from leaving Bassetlaw District Hospital on the afternoon of Thursday July 9 up until 5am on Friday July 10 when she turned up in Worksop are also currently unknown.
"Tristianna's family have been left devastated by her sudden death and our thoughts are with them at this difficult time."
Before Tristianna was taken to Bassetlaw District Hospital, her mother, Melanie Burrell, had last seen her on her daughter's birthday on July 6 when they went to a McDonald’s restaurant together.
She said: “Tristianna was extremely vulnerable and easily-led but she was kind and gentle.
“The last time I saw Tristianna we told each other we loved one another.
“That was the last thing we both said.
“We spoke every couple of days and Tristianna always knew where I was if she needed anything. I feel for Tristianna’s daughter, Kylee, who lives in America and the impact her mother’s death will have on her.
“I am supporting the police’s appeal as I want to know where she was and what happened to her over those two days. I will not rest until that is discovered. I want closure for my daughter and our family.”
Anyone who saw or spoke to Tristianna during the times as specified is urged to call Nottinghamshire Police on 101, quoting incident number 292 of 10 July 2020.
Tristianna's family has asked for privacy at this difficult time.
A file is being prepared for the Coroner.