I got treated for chlamydia 2 weeks ago but a few days after the treatment i got my period i use tampons not pads i was wondering if by using tampons i could have caused the treatment not to work ?

No worries: Your infection was treated with oral medications so tampon use won't affect your treatment. Remember, your partners need to be treated also, don't get re-exposed by an untreated partner, & for piece of mind - get a test of cure a month after your rx. Don't forget to get screened for all of the possible stds (gonorrhea, syphilis, hiv, hepatitis, etc). Take care.