My youngest son has severe autism. Since we adopted him from a Romanian orphanage, we knew that he would have some medical issues. Even so, what I heard over and over was, "just give him time" or "he'll outgrow this."
I decided not to listen to the doctors and set about educating myself on post-institutionalized children. I made copies of the articles and went back to the doctors, special education people and other therapists. After consultations and more consultations, we concluded that we were both right: some kids just catch up and some kids need extra help. I insisted on the extra help until I got it.
My son has home with our family for almost 7 years. He's made huge huge progress but is still woefully behind. At almost 10 years old, he has the speech of a 27-month old, the reading level of a preschooler and the patience of a gnat. I shudder to think where we would be if I had waited for him to outgrow this.
I tell you this story because, sometimes, many times, most of the time, moms do know best. If you sense that something is wrong with your son, something probably is. So now is the time to step up and work on this issue yourself.
Get on the internet. Type in his symptoms and see what comes up. Figure out if there is something that you can do at home, yourself (maybe he's allergic to something?). Adjust his diet, get him outside more, keep him away from people, whatever. . . Just start doing something.
Try one intervention at a time. For example, if you think he's allergic to milk or that maybe the kids in daycare are infecting him, eliminate one or the other. Watch what happens. Then try eliminating the other. Watch what happens.
Keep notes -- a diary. What he eats, what you eat (if nursing), where you go, who you see, how he acts, what he physically looks like . . . write it all down, multiple times a day (I did my son's every 30 minutes or so -- quick status like: ate yogurt, home, brothers/me, agressive, eyes vacant) If you discover a pattern, act on it.
Take your research and your behavior diary back to the doctor. Show it to him, with your research and your conclusions. Ask for his help. If he dismisses you again, ask this question: "I know that you are a wise person who has treated many, many children. I know that you have seen many, many kids outgrow something like this. But I haven't -- I have only my kid and he is sick. Tell me what behaviors or symptoms tell you that this is just a phase. Help me to understand how this is normal."
As the doctor explains himself, write it down, take notes. Pay attention. Make him give you concrete examples such as no fever, still playing with toys, smiles at me . . . whatever.
When he is done, ask this question. "What kind of behaviors or symptoms would concern you? What would indicate problems to you?" Again, write it down, take notes, pay attention. Get concrete examples: high fever, tugging at ears, loose stools, etc.
Then take a few moments to compare your behavioral diary to the notes that you've just taken. Point out discrepancies ("you said that no fever is good but look, he's run a fever three out of the last four days. What does that mean to you?")
Many doctors make quick diagnosis based mostly on experience and the theory that "if you hear hoofbeats behind you, it's probably a horse, not a zebra." Most kids have common illnesses because, well, they are common.
But every now and then, every once and a while, it's a zebra. And when it's a zebra, you two are going to have to work together to figure out what is wrong and what can be done about it. You job is to make sure that he sees all the things you see, that he considers his diagnosis carefully and that your son gets the best possible care.
In the long run, either the doctor is right and what's going on with your son is normal, you are right and there's a bigger problem here or there is some combination.. If the doctor is correct, you have the right to feel comfortable with and confident in that diagnosis. He should help you get to that place.
If you are right, the doctor should put the best interests of the child first and respond to your factual presentation of the data. He should then take more action.
If it's a combination, you guys will need to work together to find the middle ground.
Going to see someone armed with research and cold data will get you a lot further than riding high on emotion. "Experts" can dispute emotion or intuition but they have a hard time discarding concrete facts. This is your son. Take control.