Dark brown blood instead of a normal period?

and unpleasant pulling in the abdomen + feeling of illness.

So, my period started three days ago, but it was much lighter than usual, and the blood was dark brown instead of the usual red. Since yesterday and today, I've had an unpleasant pulling sensation in my lower abdomen, and now I'm also feeling weak and have body aches. It's possible that the latter is just an infection, but could it be related?

is that normal?