I think it's highly likely you WERE being dos'ed or ddosed. Considering the circumstances and the well documented problems of late i find it hard to believe that it should be anything else. Of course what Apps said should be considered first and foremost but it's one hell of a coincidence that surrendly when you're amongst the top contenders you get this problem of being dc'ed while in arena. As i said it's been well documented by now that this is going on and it's not a new thing either, it just got more widespread than it used to be. The thing is, there has been two different tactics on dc'ing opponents in arena.

#1 Using an exploit/bug in WoW to DC others.
#2 (D)Dos attacks

Most in catagory 1 gets stomped out rather fast because it spreads like wildfire and has been used in rated bg's aswell. Since it's done via actions in WoW it is also very easy for Blizzard to track and punish. So these problems gets sorted by themselves in time. The problem with this tactic is that you often can't defend against them at all - except from not playing until it's fixed.

Catagory 2 with DoS attacks is alot harder to avoid since Blizzard has little to do with it. I am sure that they will ban people who use it if it's proven, which has been the case before. Not long ago several were banned because of this, but it took quite awhile for this to happen.

What you can do, as already mentioned is to route through a proxy. Find somewhere you can get a free SSH account. Download PuTTY, connect to the account via PuTTY and have it port forward on port 1234. Then via skype have toggle automatic proxy detection and set it to socks proxy 127.0.0.1 port 1234. Close down skype and open it again. Now noone should be able to see your IP via skype anymore.

Now atleast noone should be able to get your IP from skype in the future.

You can do alot to protect your router, depending what router you have. Cisco is really good, but you probably have something in the lines of a Linksys. Linksys also has some setings that can help.

Here is a quotation from Steve Riley on Router security:

  1. Block all inbound traffic where the source address is from your internal networks. Why in the world would there be traffic on the outside that originates from the inside? This is a sign that someone is spoofing you.
  2. Block all outbound traffic where the source address isn't from your internal networks. This is the inverse of #1: there's never any reason for your network to emit traffic that's sourced from some other network. Somone on the inside is spoofing someone else (we have a term for such people: employee).
  3. Block all inbound and outbound traffic where the source or destination addresses are from the private address ranges. Defined in RFC1918, these addresses are for use in internal networks; ISPs agree not to route such traffic. Of course, ISPs make configuration mistakes, too; I've seen traffic with these addresses on the Internet. So don't trust that your ISP is perfect, block the stuff yourself. And remember to include the Windows automatic private IP addressing block. The ranges, then, are: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, and 169.254.0.0/16.
  4. Block all source-routed packets. Way back in 1970, when "routers" were Unix computers running a routing deamon, they weren't all that reliable. So IP includes a provision for the headers of a packet to indicate the route the packet should take from its source to its destination. Source-routing was necessary then, but it's completely unnecessary today: routers are some of the most reliable gear around. Source-routed traffic is the sign of an attack: drop it all.
  5. Block all broadcast packets, including directed broadcasts. Broadcasts are useful inside a network, but have pretty much zero utility between networks, so don't let the stuff in (or out). And good old smurf attacks, still seen as a form of revenge in IRC, rely on directed broadcasts. [Thanks to Michael Dragone for suggesting this additional rule.]
  6. Block all packet fragments. Fragrouter is an old but wonderful tool, imminently useful for evading network intrusion detection. With it, an attacker can create packet fragments -- TCP or UDP packets missing the TCP or UDP header -- and, for example, map out your firewall policy and prod for holes and mistakes in your configuration. With one notable exception, fragments are generally not created, so there's no reason to permit them into your network. What's the exception? IPsec -- or, more precisely, IKE authentication in IPsec. During the authentication sequence, IKE performs six round trips between the peers. As the peers negotiate a protection suite and exchange keys, IKE generates fragments: very rarely will the key fit in a single packet. So if you're allowing IPsec between the Internet and something behind your border router, you'll need to skip this final rule.

I would, if i were you, look through your router settings and see what options you have that could help you against attacks. Such as ip verify unicast reverse-path.

Try and play around with your router settings and see what you can find. I hope some of this can help you out.

Cheers and good luck