Ay sis, totally normal yan! A few of us moms went through the same thing, after removal, ang body talaga needs time to readjust sa hormones, kaya irregular or delayed periods for a couple of months ay common lang. One friend of mine had her implant out in July din, got her period in August, then wala in September din, pero by October bumalik na. Since you got your period in August, good sign na ang body mo is already responding, ang September delay ay part pa lang ng adjustment period, especially if you had the implant in for a long time. Since your PT came back negative, walang baby worries, pero best to check in with your OB/Gyne para sure lang and to rule out anything else. Fingers crossed bumalik na agad ang cycle mo next month!