Glad you're trying this! I'd strongly recommend keeping a journal like mine. It's really what keeps things going for me. I'd also recommend reading up on intermittent fasting, bulletproof coffee and fat intake. If there is anything that makes this stuff work, it's these three things(for me). All topics have already been addressed on this forum, MDA, paleohacks.com, etc. You have a wealth of (free) knowledge.
There is a guy in this forum that did a three part fasting post that is EXTREMELY well written and informative. I just concluded my first extended fast that lasted 44 or so hours. I had been doing 16hr daily fasts, then I moved up to 20hr fasts with 4hr eating windows prior to the extended fast. I'm continuing on with daily fasts at this point. So much easier this way!
Coffee. Using this as a tool to suppress appetite and increase metabolism has been key. Give it a try(especially if you have coffee provided at work!). Learn how to make it bulletproof, too..
Fat. Eat a shitload of the stuff: 80% of your daily caloric intake to be exact! You want to be in ketosis often at the beginning. Read up on MDA about ketogenic diets.
I just bought a "fitbit" activity tracker to use going forward. After my first 30 day induction phase, I'm going to up my focus on my activity. I think getting your nutritional head right should be a priority before starting a crossfit regimen or anything serious. Up to this point, I've just been taking nice long walks, some simple kettle bell exercises and a couple sprint sessions.
Keep in touch and talk soon.