You so aren't alone and so not hopeless, we are here for you.
I was thin when I was young (about 150lbs on my big bones so it looked thin, I just didn't know that til now!), met my husband and gained about 40lbs real quick (fun dates, turned 21 and drank a lot of pretty fruity drinks and ate happy hour appetizers!), gained about 25 more, lost 50, gained 100, gained 60 more, now lost 135 and still losing. Talk about a roller coaster over the last 20+/- years.
This is my last time losing, I decided. I have a good eating plan, the research I have done (and read here) on processed foods has totally changed my life (i.e. YUCK!) and now that I'm getting older my weight affects so much more than my clothes size (i.e. health) and I got really scared about my future.
We are going to be here for you every step of the way. Part of losing weight is sometimes gaining weight. We just have to try to lose more than we gain (which is easier said than done, I know).
The most important part is you posted here and now know that you aren't alone.

Now...what type of food plan and exercise plan are you doing? Is there a challenge that you might like to join here just for accountability? JollyGreenSteen just posted one that starts today through Labor Day that might be a good one for you to do. Don't set the bar too high, it can be as small as 10lbs but the important part is that you make progress towards it.
You can do it. I just know it.
