Should I take iron supplements on a regular basis?

[Theresaa]

In may this year, a blood test revealed that my iron and ferritin (22) levels were pretty low. I had to drink some juice with iron and herbs at that time. Since then not only my mood but also my endurance improved, but now, I don't drink it on a regular basis anymore.

However, as soon as I started C25K I noticed that I was extremely tired after exercise which I read can be a sign of an iron deficiency. Today, I drank that juice again before my run and notice that I'm not as tired as I am usually.

So I'm really taking iron supplements back into consideration. But I want to take low doses (about 20mg) since I know that too much can be harmful and causes side effects. And I'm planning on taking pills instead of juice since it's quite expensive. I also know that diet plays an important role but I barely can do more than I am doing right now.

So would it be a good day? And please don't tell me that I should consult my doctor because she doesn't have any time and I think she barely cares about it and where I live there are no better ones I can go to.