My cycle

Hey guys! I don't know if this is normal, my period comes twice in certain months. However, this month I already received the first one and I am supposed to have the second one in the 29th but it hasn't start yet. I had protected sex like 4 days before the time of my second period. I went over my old period, which they sometimes are late by 2days but this is the 3 day n I haven't got on it. I took a pregnancy test yesterday n it came out as not pregnant. What should I do?