1 day period while breastfeeding

Im 37 years old and still breastfeeding my 2 year old sometimes in the night..my cycle didnt start back untill my baby was 11 months ,iv noticed for a while that my periods have been shorter lighter an only lasting 4 to 5 days sometimes 2 to 3 days late sometimes day early .i notice this cycle i have only bled for a day which has not happened before .i tried to speak to me gp but they wont see me as im still breastfeeding an sometimes mess up cycles and i should wait 6 months after stopping breastfeeding to see them. I kinda worried incase it could be perimenopause but doctor's wont see.plus me and partner would like another baby could this mess things up..