to exercise or not to exercise?

I am getting married, but the happiness left me once I stepped into David's Bridal and realized that I could not just try on a dress off the rack and I was going to have to order my dress in a "special" size. What the shannanagins???!!! I have never ever been skinny, but I have never been 600 pounds either. After I had my daughter, I lost a good bit of weight. I guess we were not as activity as I would have wanted to be because now I can not fit into the size I used to be. Okay, if you want to know it was a size 8 which I am far from at this time. Fine. Now I am a size 14. Man. I hate to say it, but those late night Snickers and McDonald's double cheeseburgers did not help me prepare for the wedding dress finding. Any who, because I would like to have the option of trying on as many dresses as I want to see which ones I like best, I have decided to work my little butt off. Well, actually work my stomach off cause I need what little of my butt I have to stay. I got up this morning and went through the ondemand on Comcast for a workout routine I could do as far as cardio. I used to run, but since I stopped my knees hurt really bad when I try now so I am trying to find something low contact, but not low intensity. I found this walking program that is for 45 minutes. I was like okay this should be great. Walking kicked my butt!!!! I was panting and sweating and looking like a fool all over my house!!! Who would have thought walking would almost kill me!!!! It was so intense that I do not know if I will do it again. My eyes even hurt! My eyes! I know I probably will lose all the weight I need to lose and tone up in about a month or two just doing this for like 4 to 5 times a week, but will I live to see myself in a wedding dress when I am done???!!