Hi everyone I recently took 1g of zithromax for chlamydia about a week ago and my fiance and me don't use any protection, However my nipples have been very sore, tingling and my breast are a little heavy and full I have also been having a lot of cramping. I keep thinking its my period but its late and nothing has came my last period was October 26, could I be pregnant or could the zithromax have changed my cycle ?