Hi I Am Healthy 35 Year Old Woman. Eat Well

Hi I am healthy 35 year old woman. Eat well run 3 to 4 times a week take vitamin suppliments as needed them as I run more and natural iron,but last couple months been waking up from full good sleep tired,muscles feel weak when I run and can't run as far lately. I don't have much stress as I have a great job no kids happy life.I have been cutting down off sleeping tablets slowly as I went thru time with bit restless sleep but really should not been on them,I sleep well as I coming off them no other side effects.