That question has to be based off of someone with a needle fetish. I used to have one myself and know plenty of people that want to know how to inject any and all of the drugs they consume.
In almost every instance, benzodiazepines have such high oral bioavailabilities that insufflating/shooting them is a waste of time and can compromise your health (referring moreso to the latter ROA there).
Bottom line? Just eat/sublingual them. There's nothing much else to say. If you'd like to potentiate their effects when taken orally, use something like non-concentrate, white grapefruit juice or cimetidine (generic for Tagamet, an antacid) that inhibits the activity of the enzyme in your gut that breaks down the benzo.
You most likely feel shitty, btw, because zopiclone and similar "Z-drugs" are shitty substances to begin with. Shit substance + your brain = A shitty experience. As others have said, learn from it - and by this, I mean don't repeat it.
~ vaya