Genius idea...not so much!

So I had the genius idea to jump on the scale this morning and see how I am doing this week so far (week 2 day 3) cuz I had such a great loss last week(almost 7.5lbs) ! OMG, the scale said I am up .5 lbs!!! Now I know all the tricks so don't even start! Yes I weigh myself at the same time, under the same conditions every time so as to have the greatest consistence and accuracy. My point is, I am devastated! Mostly by my decision to weigh myself, really. I know that if I have these kind of results I will have this kind of reaction, so why do I even do it? Because I place too much stock in the numbers and not enough on how I feel.

So, my question now is, how do I stay off the scale except for my designated weigh-in days AND how do I stay positive and turn around my devastation and desire to throw in the towel? I honestly am crushed! I have been 100% on plan and even added in a little cardio yesterday for the first time and was feeling so good! HELP!!!