irregular periods

in the last 2 years i have blood spottong betweens periods. it is not every month but only sometimes. three years ago i hed chlamydia and was treated and three months ago a test showed that i still have it and i was given erythromicin for two weeks. my last four periods are longer than usual with no spotting bewtween them. my periods used to be for around 6 days and my last four are for 7-10 days and between then 25-28 days. my hormones were checked and are ok. my paps is ok. is it a problem and what check up should you recomend?

i made also US which was ok with no findings.