What do normal, slim people eat? And if I eat that way, will I lose weight too?
OP, I hope you are feeling better about yourself. I think what you have suggested is absolutely the way forward. I've been slim for almost all of my life, but I've had a few minor blips (due to changes in situation/lifestyle), where I've essentially re-learnt 'normal' eating habits to get back on track. I object to conventional dieting because I think it's often hard, too restrictive, not practical in the long-term and invites rebellion. Making and gradually implementing your own realistic guidelines seems more practical and lasting, although it may take longer than a conventional diet to lose weight (which I think is not a bad thing).
Assuming that they eat a broadly healthy diet, I'd say it's not so much what slim people eat, but how they eat. From my experience and observations, slim, healthy people manage to self-regulate their eating without too much thought (in contrast to people on a diet who ar required to spend a lot of time thinking about what they 'should' and 'shouldn't' eat).
Changing eating habits does involve some thought, application and reinforcement at the start, but after a while, this should become second nature. I'd say the main thing that people with healthy eating habits do is to eat modest amounts incrementally until they feel they've eaten enough, rather than overfilling and possibly bingeing. If I eat more than usual for whatever reason, like others have said, I'll either wait longer before I eat again and/or eat less at the next sitting. I won't feel guilty that I ate more in the first place, because it doesn't matter in the grand scheme of things.
I exercise (cardiovascular) several times a week for half an hour or so. This is hugely important to me and it annoys me when people (experts, even) downplay the importance of exercise in weight loss or weight management. Setting aside calories burnt, for me exercise is therapeutic and an opportunity to think through things and put them into perspective. It also gives me a feeling of mental and physical strength and wellbeing, as well as feeling in tune with my body, and appreciating what it can do. I always feel better after I've exercised, even if I didn't feel like doing it in the first place. I do think if your mind is generally in a good place, and you have different outlets such as exercise to take your mind off/put into perspective life issues, then that reduces the likelihood of food being consumed for emotional reasons.
I also think the idea of 'NEAT' (Non-exercise activity thermogenesis) - energy expended through activities that aren't planned exercise or necessary bodily functions ? is important, and likely to be a difference between those who are slim and those who aren't. While some people seem to move very little, others are constantly busy/moving around/twitching. The people I know who can't keep still are all slim.
Good luck with whatever changes you make, OP. And if things get tough again, please come back here or talk to someone.