I've had constant headaches for around 2 weeks, pretty much since i gave blood. the headache feels like pressure. i also tire easly at present?

Possible TTH: Tension type headache. The headaches are usually bilateral and diffuse and often have tenderness in the cervical muscles (neck) as well as the pericranial muscles. Rec.: see orofacial pain/headache specialist for evaluation and treatment.

Unlikely anaemia: While headaches are a symptom of anaemia, it is unlikely that a one off donation would have caused your blood count to drop low enough to cause these symptoms (especially if you were completely well before the donation). It is more likely a coincidence that your headache started at that time. If you are still concerned however, a quick blood test that can be organised by your GP could reassure you

Headaches : I would suggest that keep your hydration up. I don't see a reason why you should have headaches even after 2 weeks. Might be with seeing your GP as you may need some intravenous hydration to get on top of things. A more detailed history will be required .

Please see doctor: May need hydration but occasionally if people get too much blood taken out can develop anaemia (low blood count). A blood test (blood count) may be needed to exclude this plus you need examination to consider other causes of headache. Urgent medical attention if headache severe or very drowsy or blacking out.