It wouldnt be a good idea, and you would become HYPO, which would leave you very poorly, you take
levothyroxine to replace what your thyroid should be doing, and seeing you havent got one, due to a thyroidectomy,you need to keep supplementing with thyroxine, as its doing the job your thyroid should be doing. I would definately not suggest you stop taking levothyroxine, otherwise you will have some real problems and become unwell.