Ill cockerel

My poor little cockerel has come down with a flu maybe? I'm not sure so here are the symptons;
very pale comb and wattles - pale pink
loss weight - very thin althoughstill eating or drinking
Not jumping on any hens
Quite weak however i've given him some instand energy stuff
Any help would be very much appreciated

I second that you need to consult a poultry friendly vet. 

You don't say how old your cockerel is so take it that he is not an elderly bird and just showing signs of ageing.  Worm burden can cause weight loss but best not to guess and get a professional opinion asap.   

it may just be time to worm again, however, he should see a vet to be sure

Vet said worms however there's no flubenvet or anything available to buy as they're all out of stock... what would you suggest I use instead?

There are places online that you can order either the flubenvet or the layers pellets that already have the flubenvet in.  There are couple of recent topics on the shortage and where people have managed to find some.  Hope you get sorted.   

http://chat.allotment-garden.org/index.php?topic=99573.0

http://chat.allotment-garden.org/index.php?topic=99094.0