Low iron levels are an important finding. Iron is an essential nutrient that is used in manufacturing hemoglobin, which is the substance in red blood cells that carries oxygen. When hemoglobin levels are low, which they can be if you do not have sufficient iron available, this is called anemia
Anemia can have many potential symptoms, depending on how severe it is. Some of these symptoms can include dizziness, fatigue, palpitations, pale skin, and shortness of breath, especially with exercise.
If your doctor
has performed a full examination (which it sounds like they have) and hasn't come up with anything else, then it could potentially be worthwhile treating the anemia (generally, this is done just by taking iron supplements). If the symptoms improve as your iron levels rise, then you will known that this was the cause!
Of course, it will be important to stay in close contact with your primary care doctor
over the next few months. In particular, if the symptoms of dizziness do not improve with iron supplementation, then it may be necessary to perform more testing to try to figure out what else might be going on.
I hope you start to feel better soon!