I don't know if any of them lied to you, but your blood iron level might have been not at level when you went donating, and at level when you went to get it checked.
That said, before donating blood, you get asked basically what kind of wounds and things got in contact with your blood. If you want to donate blood and recently self-harmed, you should be honest and tell them. Then they will decide what to do, I wouldn't blame them for not taking the risk, they are trying to be safe, for the person that receives the blood, and for you, in case you lost blood recently and would have problems being taken more.