Help - I bled my radiator and now my boiler isn't working and it's freezing?

I bled one of my radiators as it was cold at the top but warm at the bottom, a fair bit of air came out, but no water, which I expected. The boiler started to howl after about 5 or 10 mins so in a panic I turned it off. I then plucked up the courage to turn it back on... the howling continued for about a minute and then stopped, but I noticed the light indicating the pilot light is lit wasn't on. I now have no hot water or central heating. I have noticed the pressure indicator on the boiler is at zero, so I guess I just need to "recharge," the boiler, I've done this on an older one before, which had a black lever under the boiler, but this boiler has no such lever. Removing the bottom cover off the boiler I notice it has a space to keep a "Recharging key," but no recharging key is there!
I'm freezing cold and have turned the grill and all my gas hobs on to try and make some heat.....
can anyone help me?