@ally143 I have the same thing. I ran a half marathon in May and despite months of training didn't do so great and was utterly exhausted for a week afterwards. Went to doctor, blood tests were done, and I found out I had extremely low iron levels (< 5). I also had iron deficiency anemia.
Three months of supplements later, anemia resolved but I my iron was only 17. So, I'm currently still on supplements and getting checked again after Thanksgiving. I'm vegan though so I need to really make sure I'm eating enough iron which can be hard sometimes. I'm feeling way better though. My running has improved, I'm no longer napping every day, and I'm finally making progress with weight lifting.
Three months of supplements later, anemia resolved but I my iron was only 17. So, I'm currently still on supplements and getting checked again after Thanksgiving. I'm vegan though so I need to really make sure I'm eating enough iron which can be hard sometimes. I'm feeling way better though. My running has improved, I'm no longer napping every day, and I'm finally making progress with weight lifting.