Hypothyroidism, fatigue, TSH testing.

I suspect I might be hypothyroid. I get horrible pains under my right rib cage. I had my gallbladder removed. I have extreme fatigue. I usually wake up feeling really lethargic. Eating causes me excessive fatigue. A lot of foods give me trouble. Sometimes I will sleep excessive hours. Up to 18 at times. I have a lot of the symptoms. My doctor tested my TSH about 6 months ago and it showed up as 3.536. Is that normal?