An hour or so, after I took my second pill, my head started to hurt so bad. I felt dizzy, my back & my right quad were stiff, & my vision was blurry. I spent the whole day in bed because I felt so weak. I've been on Belviq 2 full days & I've gained 3 lbs (went from 149 to 152) & my body feels weak & heavy. The only other meds I take are Advair for asthma & Synthroid to keep my thyroid cancer away. BTW I'm 40 yrs old.