What is causing fatigue tiredness while i am at home esp after i eat?

 today up at 9 am tired at 4 pm

yesterday up at 730 am left house gone til 8 ? pm didnt get tired.

is it weather?

today rain after 3 pm

yesterday clear sunny

is it stress in home? is it toxins in house. not enough fresh air?

when i am away i rarely want to nap