Will the crying ever end?

I did not have to deal with this with my two girls, but Easton is a bit different.  He is having major separation problems lately.  I noticed it first a few weeks ago when we joined the "Y" and I left him for an hour and half so I could go to aerobics class.  Apparently he cried and cried and cried and would not stop.  They tried feeding him his bottle, cheerios, playing with him...but nothing helped.  I have left him twice since then at the Y and the same thing.  We started MOPS last week and in addition to the food items I sent him with his blankie, hoping that would help....it didn't.  I left him with a friend yesterday for 45 minutes and he just cried and cried.  I am at a loss of what to do.  He does fine when he is left with my parents and he did fine this summer when he was left with my friends Rebecca and Erin.  I just don't know what to do. Sometimes I think it is the timing of when I leave him...always during his morning nap.  He is a grump at home as his naps nears and still really needs his morning nap.  The places I leave him typically aren't nap friendly, so I just hope he can make due.  Anyways, I know some people will just say-- well don't leave him with strangers-- easier said than done-- I need breaks to keep sane-- the Y and MOPS have provided me with such opportunities.  Have you ever had a child with this same problem?  I am at a loss.  Any suggestions?