Joana Burns, aged 22, had just completed a maths degree at Sheffield Hallam University when she had an adverse reaction to drugs on a night out and died.
While her heartbroken mum, Mosca Burns, was trying to come to terms with the loss of her beloved daughter, Joana's sister then took her own life just two months later.
Mrs Burns revealed details of the double tragedy for the first time on a video aimed at warning students of the risks associated with taking drugs.
Joanna died at a night out at the University of Sheffield’s Students’ Union.
The university interviewed Joana’s mum and the father of Paddy Bloor, another Sheffield student who also died after taking drugs on another night out, for an online video to serve as a warning to others.
In the emotional footage, where Mrs Mosca weeps as she recalls the death of Joana after she took MDNA - Ecstasy - as a ‘final fling’ to celebrate finishing university, she disclosed that just two months later another cherished daughter also died.
Joana lost her life in June and her sister died two months later on August 28.
Mrs Burns said: “It’s horrendous. I really miss them.”
An inquest into Joana’s death, held in May, recorded a verdict of misadventure.
Last month those involved in supplying the drug pleaded guilty to their role.
Her friend Katherine Lavin, 21, of Kentmore Close, Stockport, admitted supplying MDMA to Joana and possessing cannabis.
Former student, Benjamin Williams, 25, of Melbourne Road, Crookes, admitted supplying MDMA to Lavin, who then passed it on to Joana.
Both have been told that prison sentences are a possibility when they are sentenced on October 12.
After the hearing, Mrs Burns, from Alfreton has previously said that she hoped Joana, who wanted to be a maths teacher, would be remembered more as an inspiration for girls to take up maths rather than as a victim of illegal drugs.