Does Next Choice Birth Control Pills Have Side Effects?

About 2.5 weeks ago i had unprotected sex and took the next choice pill about 4 hours later. This was the day after my period ended. Now, today I noticed a few spots in my underwear pinkish brownish color, barely noticeable but there. I am also on Sprintec birth control and have been taking it as directed since. Could this spotting be a side effect of the Next Choice even though it is 2.5 weeks later?