I wouldn't be too worried about a once-off, but if it continues or develops into a pattern or you have any other unusual changes (eg pain or bleeding in between periods or unusual bloating/constipation) you might want to check it out with your GP.

on the other hand if you're having trouble bouncing back & the feeling of fatigue continues, it might be worth seeing your Dr for a check up including getting your iron levels/thyroid etc checked.