Few days off and now my heart rate is skyrocketing

I was off training for only 5 days.  I did manage to do a 3 mile run in there once and I did a recumbent bike for 40 min the next day but didn't record it in my log.  Anyway, today I did a 1700 yd swim in my morning and just finished a 19.8 mile bike.  Both times, my heart rate was much higher than normal.  I didn't feel tired and I was anticipating better times since I shouldn't have any fatigue. 

What happened?  Could the long (7-8hr) drive caused some of the problem?

On another note, I felt miserable having so much time off.  I think the lack of activity ruined my vacation.  It was a bit depressing not being able to log some good workout time.