Feel sad and want to cry

I feel so sad right now and I cried a lot yesterday. All other chinese childen are so inteligent and never have any problems with their study. Except my son. He is 9 now and he has so much trouble in learning. I doublt whether he has leaning disable. Yesterday he told me that the teacher said he can not move on to grade 4 because he can not pass exam. What I'm going to do? I realy want to stay at home and help him more but I have to work and go home after 6:00. I hope I can quit my job but I can not since I'm the bread maker of my family. My hubby does not have the patient to teach him. I know my son is not clever, but how can I give him up? I feel so sad for him not being clever. I know he want to be a good kid to pleas us but he could not.Life is so hard. I feel sad for my son's life, not for loosing face for myself. I only want he can be a normal kid and can support himself when he grow up. Any mom has the trouble as me?