Oo normal yan, mama! Even with mixed feeding and formula, ang breastfeeding pa rin (especially if regular pa ang gabi sessions) can suppress your period, it's called lactational amenorrhea, pero since your LO is na over a year na, baka it's time to check with your OB just to be sure everything's okay, kasi a few of us moms found out may hormonal stuff or other factors pala once we got it checked. Walang harm sa pag-confirm lang, especially kung gusto mo na rin mag-plan ng next baby or just want peace of mind!