I am tired...

We are three months into our journey, and I am tired.  I don't want to fight to communicate with my child anymore.
Since last week, we have the official diagnosis of mild to moderate autism.  People who work with him say there is no reason why he would not lead a full life going to school, to university, have a job.. anything.  And a few weeks ago you would see me filled with enthusiasm as well. He was responding insanely well to the therapies and the diet. Each day saw progress.  Pictures even showed a difference: he was clear, alert, happy, and we were getting even to the point of conversation.  For an autistic child of less than three years old, that is great.
Then Michael got a cold that lingered.  We thought first that the temporary regression was a part of that.  Now... his snot seems to have cleared up, aside from seeming rather tired he seems fine.. but the 'fog' is back so to speak.  It is harder to get his attention. He started lining up his trains instead of playing with them, something he never did before.  And his language skills are fading again.
This up and down thing is driving me nuts.  I need some solid progress again.  We are thinking of taking him to the doctor to rule out an ear infection.
I need things to get better again. I am so tired of fighting.  Fighting for therapy, fighting for time with my oldest son, fighting to reach Michael.
A few weeks ago everything seemed to fall in place.  Now everything seems to be falling apart again.