Hello and welcome!
Thank you for sharing your story. Wow, you've been managing a lot and I applaud you for your efforts to take care of your body and yourself.
It's not exactly clear how antidepressants cause weight gain. They might change how food is metabolized but if so, it's unclear how. Many people find themselves more thirsty so they eat and drink more. Others feel fatigued if the meds disrupt sleep or the meds themselves are sedating which causes overeating for an energy boost. For others, the carb cravings increase dramatically and they consume the same amount of food as they ate before plus carbs. Yes, depriving oneself of carbs can definitely lead to carb binges. I hope I've answered some of your questions but much of it is a mystery.
It is possible that antidepressants have made it harder to lose weight. As we get older it's harder to lose wight (although you're very young still!) and perhaps your activity level has changed?
I advise readers and clients to try out this way of eating and simply notice the effect. Being in touch with how food-body-energy levels-appetite-mood-quality of sleep-exercise (including what type of exercise you do) are interrelated I think gives you an inner guide for what will make you feel your best. If you can be in touch with the basics, then you can tailor it to your needs (such as the eating schedule, portions, what specific foods you eat, etc.)
Please keep us posted on how things are going for you - here's to you feeling your best!