Irregular periods

I need some advice, so I’ve been having abnormal periods for about 3 cycles now and this all started around March when i stopped breastfeeding my daughter. I thought it was just my hormones trying to go back to normal after breastfeeding for 2yrs but nothing!! I’ve tried going to the doctors but they just brush it off and tell me I’m fine? I was curious if this has ever happened to anyone before? Once again I had my period and I’m not supposed to start again until another 2 weeks but I guess my period is staying back up again!