Hi OP.
I'm sorry this is happening to you- and well done for raising it. I'm a sixth form tutor. This should be taken seriously.
Firstly, I would get rid of most of the material in brackets, because I think it undermines some of your points and makes it overly long.
Secondly, is there any chance you can reorganise it and perhaps just bullet point separate incidents?
Your email is perfectly valid, and makes important points. It should be dealt with regardless. However, as you're asking us, the suggestions I'm making would make it sound more professional. Also, when looking at bullying incidents in a school, it is very useful to have them divided out.
It's honestly fine to show that you're emotional and struggling with it- because you are. That's not surprising. If you want to sound professional, then perhaps get rid of all the bits where you sound accusatory or emotional- and just replace them with one line at the end, summing up your emotions e.g. 'I'm finding both the bullying, and what appears to be a lack of consequences, very upsetting'.
However, it's a good email already, OP. I hope you get the support you need. You deserve it.