Im taking levothyroxine ,50 mg for my hypothyroidism. im also taking several antidepressants for my Bipolar d?

disorder. i dont like the way it makes me feel.tired, dizzy, constipated and lethargic. maybe it is conflicting with my other meds (lithium, lamyctal, seroquel, occasionally for sleep..way low dose...50 mg.) i really dont know. ive heard there is are natural thyroid enhancers made from sheep hormone....or thyroxine? are these as affective as the synthetics ..like the levothyroxine i am taking, with less side effects? thank you....any suggestion would be greatly appreciated