An Update
I really thought it was going to turn out to be a good day, but....

Alex was doing just fine this morning at the hospital and the first hour, or two, after getting home.  But it's all gone downhill since about 1:00 (which happens to be the same time he was really hurting yesterday).  We saw him getting lethargic around then while playing with Legos.  He kept laying on the floor and was obviously in some pain, but was not admitting it (seriously I think he was denying it at first because he didn't want to go back to the hospital).  He vomited around 2:00 (this is the first time during this saga that he's done that).  Ate some crackers/drank some water around 2:30.  Then, he was screaming and crying about his legs hurting him.  What?  Now the legs?!  He was inconsolable, I tell ya.  I talked to the pediatrician on call at that time and we didn't get anywhere.  The fact that he didn't have a fever was good, blah, blah, blah.  Finally, Alex submitted to the idea of using a heating pad on his legs and slept for about 45 minutes.  He then woke up and vomited the crackers and water.  He fought us to no end about taking yummy cherry Tylenol, aargh!  He started complaining then about his tummy hurting again.  I've heard so many screams of "Ow" today.  It's so hard.  He's just been tired and out of it the rest of the night amidst the pains.  We hope and pray he has a good night's sleep.  The last place I want to be is in the ER tonight but, of course, we'll do what is best for Alex.

Thank you for your kind comments and prayers.  We really appreciate all of the support.