As a web designer things can be very stressful when your internet goes down if you are working on a live website or testing server. Do not panic, there is always a solution. First and foremost you should check to make sure that your network cable did not get unplugged; please do not follow this step if you are on WiFi. (hehe) If your Ethernet cord is securely plugged into your Ethernet port then proceed with unplugging the power source to your router and modem; wait approximately 30 seconds and plug them back in. From there it is suggested to restart your computer as well, but it is not always needed for your internet to pop back up. If this does not fix your problem you still do not need to panic just yet.
Contact your ISP, there could be an outage in your area and they may have an approximate time on how long it will take. Sometimes this could take a matter of 15 minutes to countless hours.
In the event that your internet ends up being down for an extraneous amount of time it is best to always have a back up plan. For starters, does your phone have WiFi tethering? You may be able to start a hotspot right then and there to fix your issues for the time being. Is there a public library near by where you can take your laptop to? This may also be a solution.
Now days internet is everywhere so there is no need to panic, if you cannot find a solution at your home or office, there is internet somewhere near by where you should be able to go! If of course your files are stored on your desktop simply drag them down onto an external hard drive or thumb drive and take your laptop and hit the road.