Getting back into it...again

So I started getting  back into it this week.  Two days of not quite 3 miles, with walking, then a break day.  Then a day with 3 miles, then 3.5 then 4.3 (a bit too much, and some walking after that).  That was yesterday.  Today is a break.  I'll see how I feel tomorrow.  I've found it hard this time to get back into it--it has felt unnatural for some reason and more of a challenge.  Hopefully this is just because I let it go too much, and not because I'm getting old.  :)