Suggest Remedies For Lethargy,weight Gain And Hungriness

Hi, i'm 20 years old female & i have most of the symptoms of having an underactive thyroid, i've had it tested a few times but have been told i'm fine, however i'm still always tierd, hungry, put on alot of weight, would it be safe if i took a low dosage of thyroxine?i don't want to go back to the doctors to be told i'm fine as i really don't like having blood taken