What Causes Fatigue With Aches And Cold?

Hi,I'm 19, female, 63kg, 169cm. Medical history: I haven't had any serious health issues in the past; other than reoccuring tonsilitis for about a year resulting in removal of my tonsils just over a year ago. I have been experiencing lethargy and fatigue on and off for the past year, generally lasting a few days. Recently I have started oversleeping alot (12hrs) and still feeling very tired and having trouble getting out of bed. I tried making my sleep more regular, going to bed at the same time each night all week and setting my alarm after 8hrs. I found it really hard to get out of bed and was still very tired. My whole body is achy, particularly after exercise. I also seem to feel the cold far more than my friends or family, I am always rugged up in coats and jumpers, even when many others are wearing t-shirts. I suspect that in the past I have had low iron, but I didn't have this diagnosed by a doctor (other than being rejected at the blood bank for low iron)