I Left A Tampon In, I'm Assuming For Probably 3

I left a tampon in, I'm assuming for probably 3 or 4 days. I have had unprotected sex twice since then and used additional tampons. I had a horrid odor and was experiencing a headache, pelvic pain. I came home from work thinking it was side effects from my Lupron shot that I started a week ago. I found the tampon, immediately took a hot bath and used a medicated douche. My temperature is 98.4, I have no discharge, and the odor is not as intense, but still there when I insert my finger inside myself. I'm concerned I need an antibiotic?