My question for you would be why does having your
weekend mean your "weekend to finally just eat" and why did you "let loose and eat everything in sight?"
It seems like maybe your plan isn't sustainable if it feels like such a prison sentence. How will you maintain your loss when you do get to goal? You said you were doing so well before, so maybe you should figure out what triggered this decision.
To answer your original question; No, as I'm sure you know, you probably didn't gain 6 pounds, some of it is water. It is possible that if you ate 3500 extra calories both Saturday and Sunday that you did gain 2 pounds, but most of the rest of the extra weight will come off in the next few days.
You shouldn't feel like all is lost, but I do think that you may want to reevaluate your plan and make it more sustainable FOR LIFE!