I agree with Rainydaiz and Angelique67 - an underactive thyroid ("hypothyroidism") is quite common.

Your GP should be able to arrange for measurements of your blood levels of thyroxine (it comes in two forms; "T3" and "T4") as well as Thyroid Stlmulating Hormone ("TSH") - measurements of T3, T4 and TSH are easy to do.

If those measurements show anything of concern your GP will be able to refer you to a specialist endocrinologist who might want to carry out further investigations and then (depending on the results of those), discuss treatment options will you.