I feel like a failure

[Lilllypad11]

Im a teacher and I’m currently a trainee and juggling another role that I feel I’m not doing well enough in and spinning other plates at work with additional responsibilities.

a large proportion of my students didn’t perform well in mocks. 16/58 of mine didn’t pass. I’m so upset, it’s much higher than the number that failed last year and I’m feeling really critical of myself. I got the spreadsheet of the students that failed and I’m shocked, I really feel like it’s my fault and that’s upsetting me and just making fe feel like I’m a complete failure as a teacher

I'm no way qualified but it really sounds like you have too much on, especially as a trainee. Could you talk to the Head and explain exactly what you've written here, don't wait until you're call in to explain yourself/the results.

I’m not a trainee I’m mentoring a trainee.

Are there classes taught by other teachers in your subject that you can compare them to?
Who marked the papers?
Check the mark scheme.
Were there particular questions that caught them out?

Is there any relationship between the marks of the failures and their previous achievement?

This is not about arse covering, but aspects the HT would expect you to have looked at before meeting, them, and yes, I'd get it in first.

All the best, OP.

What has your HOD or Faculty done to support you? You don’t say which subject you teach.
Does the school use ‘the traffic light’ system to track individual student performance. It might be useful to look at how the students performed in other subjects. There may be a different underlying cause than just your teaching.
Was there progress data, overseen by the HOD to track each students ongoing performance and interventions to support both them and you. If not it might be something that needs to be put in place.
Has anyone explained why you were chosen to mentor a trainee ( NQT? or unqualified?)