Hi, Renee! I'm happy you found this place, too!
I do think if you know that you have a hard time with carbs, the best/easiest/healthiest way to handle it is to eat a low carb diet. I also have a very hard time with carbs and sugar and low carbing has been so great for me. I would probably just try straight up Atkins, if I were you. But, read everything you can find and you may find other stuff that resonates more, or along with Atkins. You an always tweak it along the way.
A real eye opener for me was Gary Taubes' Good Calories, Bad Calories (look him up on youtube to see what he's all about, there are a couple of interviews there). Dieting feels so much different and better to me now that I know the science of it and know why the rest of the world insists that low fat is the end all be all.
My personal opinion is "no" on the dietitian. They are likely to give you the standard "balanced diet" line, which I truly do not think is appropriate for someone who is very carb sensitive. It just doesn't work. Usually they're just some skinny minny who thinks they know all there is to know about nutrition and weight loss even thought they've never had to lose a pound. That's been my experience, and I have seen a ton of them over the years bc of my diabetes.
As for OA, I haven't tried it but I've read about it and I think there is probably a lot of good there. Look in the "chicks in control" forum and read the stickies there. I think they have some about OA that might be helpful.