So last week I had to take a day off because I woke up with heavy fatigue and was super tired throughout the day with a somewhat sore throat and cough. I felt better after a day but I have noticed my heartrate on runs has been a lot higher lately. My mile pr before this was a 4:35 about a month ago and I had hopes of running sub 4:30 this season. However, I just ran a meet yesterday and was very disappointed to go 4:58. I don't understand how this could happen with only a day off. Has this happened to anyone else or does anyone have any tips for me on how to get back to where I was?