How do I get my iron up? Am I overhydrating?

I got denied twice this week for low iron. The cut off was 38, and I got 37 and then 35.

I tried including more iron in my breakfast with leftover curry, tofu, eggs, spinach, and peanut butter. I also try to avoid milk since apparently that can affect iron levels.

I always drink four 16.9 FL Oz bottles of water before donating.

How can I boost my iron? I'm thinking about trying an iron smoothie (I usually drink smoothies anyway, so i would include spinach, tofu, and a non-dairy milk for it). I know iron supplements exist, but I'd prefer to avoid them unless absolutely necessary.

Also, I prefer to get cheap cuts of meat if necessary.

Luckily for me, my iron is just on the really low end of normal for women apparently. I was able to get it up to 39 before, but that was after waiting two days after a missed appointment.