Talk to Gynecologist on Periods Issue

Im 5 months post partum afterv8 weeks of delivery i hot my periods afterr that i got period on 35 day n afterwards i start having it after 15 days i go to the gyne but internally everything is clear in uterus n all now this time i had my periods after 27 days but i only got lil bleeding for 1 day n that too was very dark close to black i never had bleeding fr only 1 day nor had blacknone ever i havnt had intercourse from 2 month so any case of implantation etc cant b happen .what should b the possible reason for this should i visit gyne our wait to have proper periods