Talk to General Physician on Fatigue And Weakness

I feel so much weakness and fatigue ! First I thought it's because of summers but now the weather is not so hot. Last month my monthly cycle got disturbed 10 days prior to actual date. I am already taking multivitamins and following the good and healthy diet. When I get up in the morning I feel laziness. As soon I start doing home chores I actively do all things. But with all that I feel to lay down and take rest. What could it be ?