Should I be worry?

I took plan b on Wednesday (with in the 72 hr time frame)

And my period just started (a day late)

But it feels so different (not as heavy)

I’m not really feeling the cramps that I normally would and I dnt feel moody

The color is darker then normal

Should I be worry?

I know that I can still have light periods while being pregnant.... is there any thing I should keep an eye out for? Or am I just over reacting