Suggest Remedy For Irregular Periods

i had a depo shot over a year ago and ive been bleeding for about 6 months after that. i have been having unprotected sex with my partner for the past year and ive noticed that my period started to become irregular. i was bleeding more and more.. i went 2 my doctor an they gave me antibiotics for bladder infection and yeast infection. im bleeding again right now only my blood is heavy, stringy unlike my other irregular periods.. should i be concerned? some one told me i could have an ectopic or molar pregnancy. could this be true?