Another workaround when dealing with firewalls is a Virtual Private Network (VPN) like TunnelBear.
A VPN takes your Internet traffic, encrypts it and sends it past the firewall to a server computer somewhere else where it is unpacked and sent on via the Internet. Data coming back to your computer goes first to the VPN server where it’s encrypted and then sent back past the school firewall and into your computer.
Setting up a VPN can be a little harder and most reputable services are not free. TunnelBear has had a good reputation and has computer applications and browser add-ons that make it easier. You can give it a try for free and see if this solution works for you.