Try not to be so down on yourself hon... yes, maybe you slacked off your weight maintenance, but it could be far, far worse. I'm fairly sure that statistics show that most people who lose and regain end up regaining more than they lost in the first place. So, you're to be congratulated on catching yourself mid-regain. Instead of just sitting back and letting all the pounds (and more) pile back on, you've come to a point where you've realized that you're regaining and that you have to do something about it. And, you're still OVER half way towards your goal!
You should be very proud of yourself for managing to lose the weight and hit goal (heh, something I've still yet to do!!!) in the first place. That is a major accomplishment and I hope that you can look back on it and find some pride and belief in yourself--you definitely deserve it.
So, you've gained 20 lbs of the weight back? Over a year? It sounds like a big deal (and okay, it's always a big deal when we gain) but let's do some math
and really think about it:
You gained, on average, .38 lbs per week. If 3500 calories = 1 lbs then 1330 calories = .38 lbs (your average weekly gain). That means you were overeating (taking exercise out of the equation) by only 1330 calories per week. Divide 1330 by 7 days in the week and we find that you were eating about 190 calories too many per day.
190 calories! That's about one serving of ice cream, or 4 fig newtons, or 2 pieces of bread....That's so easy to consume without realization! Try not to feel like a failure for such a small digression! It seems to me that you've actually done a pretty darn good job at holding yourself in check. So you've strayed a little bit here and there... it doesn't mean you can't do it. You HAVE done it, you just want to get back to goal.
I know it's hard to not be angry with yourself when you regain lost weight. I truly know. I was heavy my entire life. The first diet I remember going on was in the summer between 6th and 7th grades. I don't remember what I ate but I ran on the treadmill everyday and ended up dropping from 160 to 128. Unfortunately, by the end of 7th grade I was back up to 155. By the end of 8th I was pushing 200. I went on many crash diets throughout this time, always ended up losing some and then gaining more back. By 11th grade I was 215. I went on another crazy diet where I was eating about 300 calories a day and doing 30-40 minutes of step daily for a month. I lost 35 lbs! But, by a year later I had gained it all back. Up and down, up and down... my entire life. It wasn't until the age of 22 that I finally found something that worked for me, lost most of the weight, and have managed to maintain without too much of a problem. My point is that just because you've regained some this time does not by any means indicate that you can't succeed.
I am so much happier at this size than I was before. Though it hasn't solved any of my problems, I'm just so thankful to not feel like "the fat girl" everywhere I go. It has also definitely helped my health. At my heaviest I remember going to the gyno for birth control and they wouldn't give me oral contraceptives because I was slightly hypertensive. Now, 5 years later, my blood pressure is great (98/62 & 110/60 last readings) and the only difference is that I'm eating healthy and a lot lighter. I mention this because you brought up your and your doctor's concern about your cholesterol. If you really want to avoid the extra medication, right there is a great motivation for losing the weight again. Or at least eating healthy!
I really hope you can find your motivation. For me there just came a time when I KNEW that if I didn't do it now--and hold on to it--that I was going to be stuck in this unhappy cycle my entire life. If the extra weight and stress on your body is making you unhappy, then you owe it to yourself to achieve your goal again. Maybe try to think about where you will be a year from now, having lost the last 20 lbs again. Dieting and maintenance will probably never be "easy", but over time they do become "easier". And it's so worth it in the long run.
Think about all you've accomplished already! You can definitely get back into the swing of things, you just need to find a strong, solid reason to do it for yourself.
Best of luck to you! There's hundreds of people here who can empathize so stay in touch!