I am under the hos for under active thyroid and have iron defiency ime worried i have to go for an endoscopy?

due to constipation my latest blood test show t s h 12.78 T 4 17.5 vitimin d 99 c r p >o7 h b 13.8 u+e l f t normal calcium 2.36 can any one help with this? ime not young ime a retired lady thank,s also have to have a colonoscopy