Hi guys,
Yesterday I donored blood and everything was fine.
Today at work, about an hour before the end of shift I suddenly felt strangely weak and I almost fainted.
Someone said that I should drink something (I had only two coffees today, nothing more), so I started drinking some mineral water, but I still felt badly. So I visited our company doctor, but he said that my blood pressure and pulse are OK and that I am not dehydrated.
I am at home now, but I still feel strange and cold (but I have no fever, I have checked it twice).
Does someone know what should help me to get back into good condition?
(preferably without alchemy, spells or the ultimate help - potassium cyanide :D )

Usually happens after you donate blood. Less blood is in your bloodstream, so your brain (temporarily) has less blood. Eat more meat, try to snack on something, and try to keep awake and to do something so you don't feel faint again. You're also feeling cold too, which is also a result of donating blood. Give it a few days, and you should be back to normal.

Try some tea. Green tea preferably, otherwise any normal tea will suffice. If something bland and thin like that doesn't help, try eating something a bit more greasy, maybe you just need some food to get you going.
Usually after donating blood, I hit the gym about 1 hour later o.O

I love green tea. Anyway.

Wow, thanks for the ultra fast replies, guys.
I'll attack the fridge and try to find there something yummy, we should have at home some green tea too.
EDIT: Oh, and +rep to both of you for such speed

Not being a doctor, this cant be taken as gospel...
But I'd suggest having something to eat (preferably something quite hearty like a proper meal) and resting. Giving blood takes a pint from your body (at least in the uk anyway) and thats 1/7 of whats in your body. Your bodys currrently using a lot of resources making up the deficit pint of blood, so feeling under the weather could be down to low blood sugar, low energy or somthing similar.
I wouldn't worry too much, its a pretty common thing to be a little under the weather after giving blood but yup, eat and rest is what id do :)
hope you feel better soon dude

i too am a bloodgiver.
If you feel faint eat something sugary. It helps a lot to avoid the faintness.
Also try to drink a dark brown beer. We actually get it right after we give blood in belgium. The vitamin B inthere helps to produce new red bloodcells quicker. (yes belgium is well known for it's beer) Also try to eat brown bread.
Meat is also a good option since this provides you with a decent amount of fresh proteins.
Other then that , relax and don't do heavy activities.

I dunno, sounds to me like you're about to die.
...can I have your stuff?

Why am I not surprised?

Dude, good call! :) also anything with a good amount of iron. steaks, stouts etc.

Here they take 450 ml of blood (which should be 0,79 pint) + a small sample before the donation, but I am quite slim, so there can be the problem.
Mmmm, beer.....
Die? Me and die? I am eternal.....or at least I should be.
So.....uhm.....no, you can't have my stuff now. But I'll write a testament in case of unexpected events and you'll get something.....maybe.

What's the difference between dark brown beer and normal liquid gold? Any brands to recommend?

it's also scientifically proven
Don't go drinking pints or anything just a dark brown beer.
Try to drink more then one and you'l certainly start feeling faint ;)
Here they tap the same amount which is 500ml. (blood i mean :p )

In the normal light golden variant it's not as effective. Dark brown old beer tends to have more vitamin B + helps to clear acids and wastes in your blood.
Good variants: (go ahead on google , knock yourself out)
Leffe Bruin
Westmalle bruin
Kasteelbier
i'm quite fond of them. ;)

every discussion should end with beer imo :)