What Should I Do To Regularise My Periods Postpartum?

hi iam 36 years old. Weight is 71 kilos. I have 15months baby iwas getting periods regularly. My cycle is of 25days but this time igot period very early in 20 days. i spotted light bleeding for one day. but after that i didnot get period. never this happened. This is the first time. Please tell me whether thers any problem. Iam worried. What should i do to regularise my periods.