I used to eat spinach the week before I tried to give blood, it always worked for me.
I've been eating (well drinking) a baby spinach, almond milk, banana, wheat germ, handful of peanuts, smoothie for breakfast every morning, make me feel better.
Smoked oysters have iron, raisins, if you're taking a supplement I think chelated is recommended for absorption if that's your problem. When I was younger my doc prescribed a vitamin for iron deficient anemia, I try to get the nutrients from food now, spinach works the best for me.
you'll find what works for you, best of luck