Memang biasa saja, sis, a few of us mums experienced irregular periods macam ni after bersalin, especially kalau still breastfeeding sebab hormone prolactin boleh delay haid. Pregnancy test negative is a good sign, so most likely body is just settling back, tapi kalau dah lewat lama sangat or you're worried, better check with your doctor to be on the safe side, especially if breastfeeding status ada berubah recently.