HR sky high?? Could this be do to last race?

I completed a HIM almost three weeks ago.  I took a week off, then got sick for several days, and finally got back to running.  Now when I run, to keep my HR in zone 2, I have to run about a 2-2.5 min slower pace than I did before the race.  I did a nice easy 10 miles Sat., and even though the pace was slowish, and I felt good, my HR was 85% of max.  My legs were also sore the next day, which doesn't happen often.   

And my swimming.... I'm dead after only about half my regular distance.... and my back was very tight the next day.

Has anyone had this experience after a race, or could it be something else?  

I've only been using a HR monitor for about 3 months now, so I've never noticed the elevatid HR before, and I usually take a long brake after a big race.