I am still nursing my 10 month old and my cycle has not returned yet. A few weeks ago, maybe 6, he was on a course of antibiotics for an ear infection. A week later my nipples hurt like they were sunburned, very sore. I thought it might be thrush from the antibiotics but he had no sign of it. Following that, I started having dizzy spells, fatige, and nausea. I took a few pregnancy tests over the past 4 weeks and they were all negative. Any ideas what this could be? I feel pregnant, but apparently not.