Period comes early stops then starts again

Hey everyone! So I am having serious period confusion. Last month my af came two days early. Then stopped for two days. Then came again. This month it came two days early then stopped and is all light and not normal. I'm semi worried it's not a period but implantation bleeding, but then it happened two months in a row. I also got in a car accident two months ago. I didn't have any injuries other than sprains and bruises, but that's the only weird thing that's happened.