Talk to Gynecologist on Menstrual Issues

Hello, My age is 29 years and my periods come on regular basis i.e after 28 days but from the last 3 to 4 months I observe that the blood flow is slow and not strat on the first day. On 1st day it's just like spotting and after 24 to 36 hours few blood releases and after that fully started and on the 3rd day it disappears. please suggest me is it normal or I need to consult a doctor for treatment.

Thanks