Aww, Karen, please don't be so hard on yourself. It is perfectly normal for a woman's weight to fluctuate about 5 pounds. Add the water weight and you may not have gained as much as you thought. Just make sure you are keeping your metabolism up and eating regularly. And give your self a big pat on the back - losing 75 pounds is no small feat!
I agree with the others, you are being waaay too hard on yourself. You have lost the weight before and you can do it again. Temporary water weight gain is just that: temporary! I was watching the Tyra Banks show the other day and they had an expert on there that said you can eat as late in the evening as you want, just not 1 1/2 hrs. before you go to bed. Sounded good to me.
Don't beat your self up over a temporary setback. Have yourself a good pity party and then get on with business. Remember what Scarlett O'Hara said: Tomorrow is another day.