Fatigue

Hi all, I feel exhausted all the time and as I’m getting older I feel as though my PMDD is coming on earlier and stronger and really wiping me out. I’m just wondering if any lone has experienced this and if there might be some kind of underlying condition or illness? For example, if I go for a run following my ovulation days, I feel like I’m going to pass out, and I’m talking under 5kms and not very fast either. Any thoughts or help would be really appreciated.