What Causes Tiny Rashes Like Bumps And Itchiness In Body?

Hi. I've been having itchy skin since early May. It started while I was at school living in a dorm room with 3 other girls. It wasn't bad until June. By then I had already moved out of my dorm. I went out one night and got 5 bug bites. Then I left for the weekend to move back to Manhattan and got 3 more bug bites. My itchy skin got worse and the rash looks more like tiny bumps on my hair follicles or like goose bumps. I don't know if it has anything to do with hot or cold weather. But this whole entire time ever since May, it's been disappearing and reappearing. It's never on my face or my feet. Tonight I just developed a headache. I'm not sure if it's part of my rash since I was around people that were coughing and sneezing for the past few days. What is wrong with me?