Here's my story. 3 weeks ago i had run the best race ever. Not fast by letsrun standards but it was a 17.41 5k. The next day i had the flu and 4 days afterwards i felt better and resumed with normal training although my lungs werent fully recovered. Since that flu my easy pace is now much slower and today i decided to run some long intervals uphill at vo2 max. But after the first one, my heart rate stays at 125/130 for 2 minutes in standing rest. So i decided to quit the whole workout. Is this normal for vo2 max workouts or am i overtraining ?