sis,as what I've known there's nothing to worry at all.Yeah the doctor from Hamad is right that incase they are query of something in your chest they will send you in TB clinic in Rumaillah for some laboratory work-out.Then if they will find & check that there is no active lesion they will give a clearance that the Medical Comission might considered.So as you said that you had undergone already all the test and it turned out negative so no reason for you to worried already.
Anyway, just keep on taking care of your self & keep your faith up.Keep on prayin and hopefully everything will be okey.
Cheers!!!