What Causes Headache, Weakness And Lack Of Concentration?

Hello doctor, i am 19 and for the past few days i have been experiencing symptoms such as intense headaches on the right side of my head or right forehead, at times i experience intense physical weakness, fever and lack of focus and concentration, i am also having trouble to remember things in my short term memory, the latest symptom has me worried, I am struggling to speak at times, I cannot remember the words or even how to say something, this also comes when I am having trouble thinking or focusing. These symptoms come and go and i have no idea what is going on and it's frustrating me and the people i work with.