Am taking generic Septra DS (bottle says SMZ/TMP 800-160). It is making me extremely sleepy, and somewhat dizzy with a general cloudy feeling in my head. I went downstairs to my car earlier this morning and the back up the stairs and had a hard time catching my breath. Anyway, I thought all this might be me just freaking out because I am paranoid of medicine, but I took one at about 5, took a shower, got ready to leave and just found myself sitting on the lazy boy, so tired that I just had to go to sleep. I have been sleeping all day. Is these symptoms of a possible allergy to the medicine? Its an antibiotic. Its not supposed to make me feel terrible, right? I just have an infection on my toe.