Well I'm no networking expert or anything but you could try setting up a tunnel on your home PC and connect to it at work and you can browse just as you do at home, just that your PC will act as a medium between your PC at work and the internet, so it will be slow but I guess it's better than no internet.
As for tunnelling I personally prefer having an SSH server at home and tunnelling everything through SOCKS. It's real easy if you use Linux but if you use Windows you might need to
jump through a few hoops to set one up. The best part is it only takes one small program (PuTTy) and 30 seconds to set up on the end your connecting from (your work PC). I use it from school and not a complaint, works perfectly and all the time, just a bit slow, but as I said, better than no internet, or tons of blocked sites in my case.
The only other solution I've read about is using
Squid. You set it up on your computer at home, but you'll need a web server to to do that, XAMPP works great in this case imo. I don't know any of the details but in the end you'll have the same thing just that the proxy is an HTTP proxy which I've never used before so can't comment but I imagine it'll be the same thing except for what's going on under the hood.
The only problem you may face is if you have a dynamic IP like me, in which case you might need to set up a dynamic DNS using a site like
DynDNS. You just their client running and it makes a subdomain constantly point to your computer, so in my case tidusblade.ath.cx always points to my dynamic IP, so I don't have to worry if my IP changes.
Sorry if I was unclear or wrong in some places, as I said I'm not great with networking and stuff but this worked for me perfectly so hopefully it might work in your case

Only way it might not work is if they block direct connections to other computers across the internet, but I've never seen that being done so I don't know, maybe someone else can clear up.
Good luck
