I'm supposed to give blood today which I've been doing for years without any problems. However last time I did it (since going on HRT) I felt so drained (ahem) for a couple of weeks afterwards. I had no energy to do much and I really need to be on top form at the moment. I take iron supplements anyway and I'm assuming it's not the HRT itself that's the problem. Anyone else had this problem? I'd feel very guilty cancelling.