Fifty pupils were reported to have used the service in one term, and teachers now hope Ceredigion education authority will fund it permanently.
Lynwen ap Gwynedd, a teacher at the school, has responsibility for family and child well-being, a new role introduced to promote personal and social education.
"Pupils knew that they could get an answer to their problem without having to explain it face to face," she said. "Our ethos here is to be child-centred and to create an environment where pupils feel their problems can be addressed."
The school was praised in a recent report by Estyn, the schools' inspection agency, for the way it delivers personal and social education.
Despite falling in recent years, teenage pregnancy rates in Wales are still the highest in Europe, and rates of sexually transmitted diseases among 16 to 19-year-olds have risen.
Estyn said: "Good-quality teaching is the single most important factor in ensuring an effective sex and relationships education programme in schools."
It found most schools provide good or very good PSE teaching, and that single-sex groups are far more effective when dealing with issues such as sex and relationships. But the report found that many teachers still feel they need further training in this subject. A report by the Assembly government in 1999 said there needed to be "better communication and a wider understanding of sexual health" to address sex and relationships issues.