Weird period?

I usually have abnormal periods. By abnormal I just mean it never starts when it’s suppose to. It’s either 2 days late or 2 weeks late. When I do get my period I usually get precramps telling me it’s coming soon. when it starts it’s usually really painful the first to days at least and heavy. But this month, I had no precramps, my period was only about a day late & I have NO cramps at all. It’s also pretty light for it being my 2 day. It’s also really dark blood instead of normal red I guess you could say? Is this normal?