I Got Banned From The School Network!

Well today I was walking in the corridor when the headteacher of the school stopped me. He then asked what is my name. I replied “Sebastian Hughes”. Then he said come with me so I went with him and he took me to the ICT place. They then asked me if I made a program in excel that enables messages to be sent across the network. I said I did. All it did was have a form and used the net send function. Then he said it was my fault everybodys using it and that I put the network security at danger. Then he went on to talk about he did want to have to spend thousands of pounds to increase the network security. Then he want on to say that i was breaking copyright law or somthing poo cause I had some software on my account. Which were all Open source. The headteacher in my opinion was talkign bull**** lol. The Ict person gave me the same talk but he then asked to see my USB stick, I had nothing to hide. So i showed to to him and i watched of course as he wenmt through it and there are alot of exes on it. He kept asking what this and this program does I explained to him open it. He could tell he was scared to open the files and he like hand was shaking over the mouse and after a while he ran the program and all it was, was a simple calulator i wrote in C++. He then said I was under investigation and crap and he took some progra,m of my usb to investigate them. They were 7zip,firefox portable and Wget. Which IMO was dumb cause therenormal program. So im banned for 2 weeks and if they find out I compromised the security even more with what I had on my usb and crap I could get a life time ban. I told my mum was she bothered No. Also they are sending a letter home about this. Which i will frame and hang on my wall. Also they said I hacked into a part of the server called the “active directory” or somthing. Well thats my story. To be honest I think they went OTT. Now my accounts under investigationetc.