Teachers have said working through another lockdown has pushed the profession "close to breaking point".
While most pupils across England have been told to learn remotely, schools remain open for vulnerable students and the children of key workers.
School staff in the South West said they were working "incredibly hard" to make the lives of students "as normal as possible".
Some said their workload had "never been higher" as a result.
Teachers across England had to "start from scratch" when they were faced with the prospect of lockdown learning, said Dan Hayward from Ivybridge Community College in Devon.
The head of history said running parallel lessons for children in the classroom and those at home meant he had "never worked this hard before".
"This is working up to very late at night, this is sacrificing a little bit of our relationships at home."
Mr Hayward said a lack of clarity over how exam grades would be determined this summer had led to feelings of "confusion, worry, and anxiety" among the teaching community.
"The government are suggesting more and more work, at a time when I think there should be that little bit more sympathy for a profession that is close to real breaking point," he added.
Tayla Brown, a newly qualified teacher at Teign School, near Kingsteignton in Devon, said Covid forced her to complete the final half of her training online before starting the job in September.
The 23-year-old history teacher said she was working "incredibly hard" to meet students' needs, "whatever that meant for me".
"This is not how we ever envisaged doing our first year of teaching.
"I just think in general everyone is tired, and not just emotionally, but physically, mentally, because it's been hard work."
However Ms Brown said her passion for the job, and "incredible" support from her school, continued to motivate her through the pandemic.
"I love teaching so much, and I think that's probably what has guided me through," she said.
Jenny Walker, chief executive of Kernow Learning Trust, which brings together 20 schools in Cornwall, said lockdown was "tough for everybody", including teachers.
Her words were echoed by another head teacher, who warned staff were working through an "educational crisis".
"I think they're tough, but it has been tricky for them," said Mike Johnson, executive head at Chulmleigh Academy Trust in Devon.
"The whole situation when we come back is going to be completely different," Mr Johnson said.
"So we can't just give the same resources and do things in exactly the same way as we did before the pandemic and hope everyone is going to catch up and everyone is going to be okay.
"If we do that, we're preparing for a world that no longer exists," he said.
The Department for Education said: "We are enormously grateful to teachers and other school staff for the resilience and commitment they have shown in supporting children during this challenging time.
"We have taken consistent action to address teacher workload and wellbeing and invested millions in mental health charities to support teachers."