When you came to Qatar, you should be aware that your visa is personal, under which, after six months, that NOC issued to you is called "Tahsera" but before you were given that you must have a new employer already to take over for the transfer of your visa, why did you go out the country? You have NOC, you can transfer to other employment...but now that you went out of the country, with cancelled visa, you need to approach your old sponsor to lift up the ban...and come back with all your expenses and should come with ready employment.Someone should talk to your sponsor before coming back to clear all things out.