Hi @howlor5 welcome to connect. I can definitely say Iron is a factor in feeling fatigued as when I started this thread my wife was going thru a similar situation of low iron. But also I myself have had bouts of low Iron and am now myself back on iron pills. My saturation is 15% but except for a slight bit of fatigue a quick afternoon nap helps a lot. I'm retired so if your someone with an active schedule like work or kids I can imagine it can be difficult.

What i can't really address is if it's because of the other issues you mentioned. I'm not familiar with how the treatment for the cancer may also be a factor. I also have low platelets and when it drops down it also affects my energy. I personally don't have any shortness of breath issues now, but I did when I had heart problems so it may be something to get checked out.
Also if your already seeing an oncologist they may be able to help with the iron issue. The doctor i see for my ongoing anemia is an oncologist. I hope that may help a bit. Let me know if I can help further as I know ever since I found this forum it has helped a lot to just know that others share in what we are feeling.
Have your doctors decided on any further testing to identify what else may be at play? I myself came from a background of heart related issues and my anemic issues came about due to the suppression drugs required for a Heart transplant patient. I've heard that the anemic issues are similar to people who have ongoing cancer treatment. So, please let me know how else I can help.