Writing on the WalesOnline Facebook page, Julie Brooks, from Tonyrefail, near Pontypridd, said her 15-year-old son Simon was made to attend school 'despite what he was enduring'.
She wrote: "He is now dead after taking his own life.
"I used to physically wring my hands as Simon left for school. I'd stand in the hallway and say to myself 'what can I do?'
"It was horrible and I felt helpless because I was damned if I sent him to school and damned if I didn't – it was so frustrating."
Simon, who attended Y Pant Comprehensive School and had been bullied for most of his life, left his mum a goodbye note in which he told how he wanted to be with God.
He died in April of a drugs overdose.
Julie felt compelled to share her grief after schools across South Wales were sent guidelines recommending pupils take 'zero days off' school, even if they're ill with such childhood complaints as tonsillitis and glandular fever.
The booklet does not refer to bullying and deals only with illnesses, but Julie described it as 'ludicrous' and felt the need to vent her 'anger and frustration' about it.
She said: "This booklet emphasises that fact and makes what I was feeling at the time very tangible.
"This booklet is all about making schools look good and not about the child's wellbeing.
"It's targeting all the wrong things in all the wrong ways.
"I'm hoping the combination of things will get the booklet discontinued – it's complete nonsense.
"If a child gets tonsillitis, they're sick, and if a parent takes them to school, the school will only ring the parents to get them to collect the child.
"To say I'm angry is an understatement. It's about allowing the school to decide if your child is ill or not and the booklet has not been given any thought."
The booklet was published as local authorities across South Wales are being put under increasing scrutiny by education watchdog Estyn to improve their attendance levels.
It also says children should spend five days off school for chicken pox, four days for measles, five days for whooping cough and five days for mumps.
Parents are told to inform their school of their child's absence at 9.30am every day. By law, only the head teacher can authorise for a pupil to be off school.
A spokesperson for the Central South Consortium said: "The medical advice printed has been obtained directly from the Health Protection Agency in England in conjunction with the Royal College of Paediatrics and Child Health.
"Consultation was carried out with Cwm Taf, Cardiff and the Vale and Abertawe Bro Morgannwg University Health Boards and Public Health Wales who all approved the content of the advice table."