Behavior Issues help!

My son was recently diagnosed with SPD and along with it has a lot of food issues/allergies and candida, skin rashes etc.  In a lot of ways I'm very fortunate he doesn't have any other type of issues.  However, we are in a downward cycle with him right now and I just feel like nobody understands.  I feel like when he has major fits that other moms look at me like I'm a terrible mom and that he has behavior issues.  I just don't know how to deal with him, the past couple of days he hasn't taken a nap which has escalated his behaviors and he screams in this evil sounding voice and shakes his crib back and forth in his room until I let him out which yesterday I gave in after 30 mins and today after an hour (only because he fell out of his crib).  I mentioned to a friend of mine that it was a rough day with him and she said you know I've heard you say that a lot before, but when I see him he acts just like any other 2 year old does.  I don't know why but this really bothers me.  I feel like people don't understand what I'm going through and like I'm going a little bit crazy.  But anyways I was just hoping to see maybe somebody else who could relate?