The summer of 2018 will not be fondly remembered by many 16-year-olds. There were stifling sports halls, sleepless nights and sweeping changes to GCSEs that left many fearing the worst come results day.

It was no surprise, then, that the overwhelming feeling was relief when students at two schools in Manchester ripped open their envelopes on Thursday morning.

“It’s been the most stressful period in my life,” said Mard Khoshnaw as he boasted a string of 8s – or As and A*s – where he expected 6s. The 16-year-old said his teachers at William Hulme’s grammar school in south Manchester were great but were “in as difficult a position as we were” under the new, tougher GCSE structure.

The lack of past papers made it impossible to know what to expect, he said: “As soon as I got home I’d think about the exam, then think about the exam the next day. You have exaggerated thoughts like how you might end up homeless. You want to choose your future and it’s so scary thinking it’s one exam that can do that.”

A former fee-paying school, William Hulme’s is a city academy where half of its 1,300 pupils qualify for government funding as students from disadvantaged backgrounds. It is in the top 18% of schools in the country for pupil progress. This year 57% of its students got level 5s or above in English and maths, compared with the national average of 40%, and 72% got five GCSEs at grades 4 or above.

More William Hulme’s pupils receive their results. Photograph: Christopher Thomond/The Guardian

Ahmad Yusuf, 16, was one of only 732 students – and one of just 278 boys – in the country to get seven or more grade 9s. “I didn’t want to expect 9s because it’s such a high grade,” he said. Yusuf managed a clean sweep of As and A*s with 9s in maths, biology, chemistry, physics, food preparation, PE and religious studies, eights in English and a 7 in German.

“It’s important to remember that exams aren’t the end of the world. I didn’t get myself too worked up about it,” he said. “It’s just important to learn it properly at the time in class – a bit of messing round but not too much.”

His classmate, Mohammed al-Kalbani, had good reason to feel proud. The 17-year-old did not speak English when he arrived in Britain last May. His family fled from Palestine before he was born and his father brought the family from Romania to Manchester when he found work last year.

Kalbani rose quickly to the top sets when teachers spotted his ability and his rapidly improving English. On Thursday he got a double 9 in science, 9 in religious studies, 8 in maths, 6 in English literature and a 5 in English language. “I’m so happy this school gave me the chance to do GCSEs so I wanted to work really hard so I didn’t disappoint them,” he said.

Across the road, the relief was palpable at Whalley Range high school for girls. “It was so stressful, exam after exam. I’d go home, stress about it, cry, eat food, cry more. I’m just so glad it’s all over. The new grading system was stupid,” said Maryem Eblish, 16, who got an 8 in sciences and a 7 in French, “which is so surprising because I gave up half way through – it was gibberish”.

Students collecting their GCSE results at Whalley Range high school. Photograph: Christopher Thomond/The Guardian

Such was the pressure on this year’s cohort that teachers ran mindfulness classes, where students were taught yoga and stress relief. The school’s headteacher, Elizabeth Hole, said: “There’s no doubt there’s a lot more stress with all the exams at the end because there’s nothing in the bag for the students – there’s no coursework. They had to do it all at the end.”

Despite sleepless nights and a fear of the unknown for students and staff, Hole said she was pleased with the school’s results: 65% scored grades 9-4 in English and maths, up from 63% last year.

The removal of coursework did not seem to affect the girls’ results as some had feared it would, she said: “We thought it might have impacted more on the results and it hasn’t. That comes down to how the staff have prepared the students.”