Honestly, it's so individual. It's wintertime, so you are not eating fresh local produce anyway, so everything was grown in another country, picked early, and shipped here. You have no idea what's in the soil anywhere unless it's your local farm, so the freshest produce can still be nutrient-deficient. You've built up a lot of "stuff" in your body, from toxins to "sludge" coating the walls of your intestines. Absorption is affected, obviously, so what you chew and swallow is not necessarily what gets into your cells. But that's true of everyone, at all times of the year, to some degree.
Anxiety is a tough thing, as are other issues like depression. You may be on the seesaw of wanting to exercise but not having the energy to do so, so you don't get the mental boost from the exercise (endorphins) or the faster metabolism or the cardio benefit.
The body takes a while to detox, certainly - but please don't rush it by doing one of those fad cleanses! They are so so stressful for the body and they can be dangerous. I work in food science and do a lot of education around this, and I can tell you that comprehensive nutrition (generally with high absorption supplements) and slow, regular, safe detox can make all the difference. Slow and steady wins the race - but we live in such an instant society that we are very impatient. You have to have reasonable expectations of your food - it's very well known that today's food just doesn't have the nutrient content it had 40 or 50 years ago, so we have to eat thousands of calories more to get the same intake. Hence we have to supplement - responsibly and with non-GMO products that work together (no single or isolated nutrients or vitamins).
I battled clinical depression for years - while I didn't have the anxiety that you do, I work with a lot of people who had one, the other, or both. For me, it took 3 months of really solid cellular nutrition (science-based, no fads) to get healthy enough to just not have bronchitis and colds all the time, and 5 months to get off my antidepressants. It took a good 6 months in a fun class of women in my general physical condition (not muscle men or 20 year olds - just a supportive group) to get to the point of lifting enough weight to build muscle. And of course muscle burns more calories than fat. I used the class for my strength and stretching, and alternated with treadmill work for cardio - and I always read a good book on the treadmill to pass the time. I read some mysteries (to occupy my mind with the who-done-it details and keep my eyes of the timer) and I read some self-affirming things, and I found it was better to NOT read the People magazines with all the gossip and focus on skinny actresses.
I think the thing to do is to make each day just a little better than the one before - walk a little farther or do it a little faster, go up one notch on the weights every 2 weeks, etc. Track your repetitions and weights - if you use a gym, get one of those cards that lists which machines at what weight, etc. DO NOT get on the scale every day - don't track that at all. In general, you'll find your clothes fit better before the number of pounds on the scale goes down. Don't give up. Get a pedometer but don't go crazy with the 10,000 step goal. Just do a few more today than you did yesterday. Park a little farther from the store entrance, walk the long way if you can, take a stroll around the block or walk the dog when you feel down. And don't beat up on yourself if you have a chip. All things in moderation.