Wow, I did not expect so many great responses so quickly! Thanks everyone. I did forget to include that my son is four. Currently, we live overseas as well so I don't have access to any services. I've decided to bring him home and stay with my folks for awhile so I can go to some doctors and basically just have my mom's support.
Maybe I will take him to an occupational therapist...I am also going to institute a chart for good behavior stickers and a private chart of my own to track the tantrums along with his food intake, etc. I sure don't expect my kid to be perfect, Lord knows I'm not. I just want him to be happy and well-ajusted.
Let me see - autism has been ruled out and yet your son has "tantrums and obsessive behavior" (your words). I'm wondering if the issue is OCD - your post definitely indicates this could be a possibility. I might suggest you google the phrase "OCD in children" or "anxiety in children" or similar words/phrases to see if the descriptions remind you of your son. By the way, sensitivity to certain items of clothing, tantrums, and inflexibility are common behaviours to children suffering from anxiety. I wish you the best ....
How old is your son? Maybe a discipline chart would work. For instance, put the days of the week on it and let him choose a reward. After so many stickers on it he can earn his reward. Its like setting goals. He sounds like he really needs some mommy and daddy attention. You need to ignore the bad behavior and reward the good.