What Causes Fatigue,headaches And Hot Flushes?

Im a 19 year old girl and recently ive been feeling really sick this has been a constant problem for around 2-3 weeks now. Aswell as feeling sick i have been sick a couple of times, i get headaches everyday which are really strong & i get really bad hot and cold flushes. Ive had the contreceptive implant in for 2 years now so i dont think i can be pregnant, Can you please help me try and figure out what is wrong with me