AC Self Adjusting to Heater

I live in AZ and the temperature was 115 on Friday.  I was running my AC
when I stopped at the store and was back in the car within 10 minutes.  
When I went to restart my car, AC was not coming out of the vents and when
I went to the Climate setting on my UConnect, it showed that the arrow that
was on blue for cooling had self adjusted towards the red section for heat
and everything was adjusted to the heater/defroster.  The same thing
happened yesterday when I stopped someplace and got back in the car to
start it. I've had the vehicle since it was brand new and the temps outside are
nothing new over the summer.  I'm not sure why this is happening now.  I
have not had to replace my battery yet since I owned it.  Is this a sign that
that battery is going out?  Additionally, a few months ago I realized my Auto
Stop/Start is no longer working.  I really don't mind that it doesn't, but could
the 2 issues be related?