15 to 20 pounds may seem like a lot, but we have all known women who were 50 to 60 pounds over weight and looked great - it's all in the attitude. One of my best friends is that way. She is so well groomed, so self confident, and pretty darned smart to boot that people don't even see, let alone think, about her weight. I know she does from time to time, but her philosophy is change what you can, and let the rest go.
Sometimes you just have to wait until the right time to take control over the weight. That has been the case with me. I am research scientist with lots of pressure and responsibility, and before that I was a PhD student, and before that I put myself through college. I just didn't have the time or energy to focus on my weight problems until quite recently. At the moment the career is on auto pilot, so I can focus on losing the pounds for a few months, it has been a wonderful diversion!
Like all of the women who have replied, I am more concerned about how you feel about yourself than about how much weight you are carrying. Be kind to yourself. You are only human. Have a good cry if that makes you feel better, then take a step forward. Imagine a bright future and keep your eye on it and do your very best not to dwell on the past.
Most of us have been where you are at one time or another, as you can see from how many wrote to tell you their story. Seeking help is a sure sign of strength - build from it.