I've been taking Levofloxacin for 3 weeks now (for my bronchitis)...

I've been taking Levofloxacin for 3 weeks now (for my bronchitis), and ever since I started, I've felt uneasy. I'm experiencing severe nausea and mild stomach aches (that sometimes lead to vomitting). My head feels heavy and my stomach's so bloated that I feel even more sick than I already am. This is the first time I've ever had this kind of experience with an antibiotic. I'm a college student, and it's so hard for me to deal with all my academic demands while suffering from the side effects of this drug.