You said you don't know what your goals are, no one should go into a 'fight' without a plan. You have to know where you want to go, or what you wish to accomplish otherwise you run the risk of a circular argument that does more harm than good.
Wait until your head is clear. If he asks what is wrong, tell him your having a rough day and don't want to talk about it right now, just emotional or something. Wait until you have a plan/goal/objective.
