The 3 of Swords is about assertiveness.
Sometimes you just shouldn't ignore those others that do you harm (conciously or not). Sometimes you should face them and force them to respect you.
Now is definately the time to get more assertive with someone who's probably testing you for a while now. Some people just won't quit until you tell them to, so you'd better tell them quite early.
You've cropped up your feelings for too long, and you feel like telling someone who's been testing you the full truth today. Probably not a bad idea to show them you've had enough.
Don't be too vigorous in your complaints to others right now. Either the time is not right, or you're planning to bark up the wrong tree.