New patterns symptoms and conditions

My son is 8 and he has been on singulair for at least three years, maybe four. When I heard about the side effects a few weeks ago, I stopped his medication right away. I have since learned that it should be tapered off, but won't put him back on to do that. He had so many of the depression, I hate myself, everybody hates me, facial tic, stomach ache symptoms . . . Now he is almost two weeks off of singulair and he is throwing screaming fits, kicking, threatening, uncontrollable for up to two hours and more! Is this a side effect of coming off of the medication? Has anyone else had this experience? Please email me at amy-weaver4@sbcglobal.net - I'd really like to hear if anyone else has experienced these symptoms. Thank you! Amy