Delayed menstruation

Mommies question po, ever since I gave birth laging delay ang menstruation ko either 5 days minsan 7 days delay.. dati kasi sa Calendar na ginagamit ko sakto lagi.. ever since nagkaanak ako nagbago na, 13 months na si baby breastfeeding pa din. Normal lang po ba or need ko magpacheck up? #pleasehelp #advicepls #firstbaby