Jaguar Boiler - F0 flashing after I bled the radiator. Loss of pressure!?

Hello all. My wife is currently not speaking to me, so I hope you can help.

I have read through the answers here, but nothing quite seems to have helped.

I bled the bathroom radiator and had an immediate loss of pressure resulting in cold water only. The radiators also don't work.

When I follow the handbook, it says that by turning the tap I should be able to see the pressure gauge coming up on the bar button, but I can't - it resolutely stays at 0.1 bars.

I may have got frustrated and turned all the valves/knobs - and unless I turn everything wide open, it doesn't even make a sound - so I am guessing I have mistakenly drained the whole system. F0 still flashing on the control panel.

Can someone please walk me through step by step as to what to turn on or off (I would prefer red valve or orange tap to any technical jargon) so that I can get the heat back on without calling a plumber on the weekend?

Help me not be cold or lonely!

Thanks

Rich