Okay so my period is usually around 5 days and then some spotting afterwards for a few days if I have sex. Well this month I felt different before it, and had super bad mood swings and I got it a day early. I was like okay so I'm not pregnant. Well I go through Day one which was a little heavier than a normal day 1 but still normal, day 2 was a little lighter but still heavy enough to be considered normal, and then Day 3 was like my usual day 4-5 and now it seems like it's over. No more cramps or back aches. Is it okay for it to be shorter one month and then go back to normal? I took a pregnancy test to make sure it wasn't implantation bleeding and it came up negative so idk of my body is just messing with me and it's gonna come back in a day or 2 and then finish up or what. Anyone ever have this happen before?