Thanks to all of you for your answers! I hope that the things would be better for you too!

@online user have you checked whether you have GI deficiency? I know that some people with such deficiency have digesting issues. Some foods would cause too fast emptying and others would cause constipation. Have you thought about that? I took Nexium as part of my treatment too. It was temporary though. I have to mention something though. Aside my binge moments I actually eat healthy - I don't mix foods, I don't eat fried foods etc. So aside the fact that I have bile in my stomach, it actually looks totally fine. No ulcers, nothing. So my healthy eating has positive impact on this. As a result I don't need to take Nexium permanently. I do have heartburn, but I could deal with it. I just put cinnamon in the foods that I eat and could go with it. Ginger works too btw. And putting lemon drops in the water you drink. If you have diabetes cinnamon is good for you because it lowers the blood sugar level.

For the constipation I do try to eat more fiber foods and take fibers as supplements in the morning and the evening before eating.

@Piraeus I do try to research about this. Well you never know whether the information is correct or not, but it's better than doing nothing. In fact currently I'm checking the possibility if some hormones and neurotransmitters (like serotonin) have impact on my stomach and mental health in the same time. For me food really does have impact on my body. Certain foods give me energy and others just drain me. So in the end of the day individual approach is needed too.

@Raindropvampire thanks for the tip about elevating the head. I've read about that, I just haven't done it so far. I don't have heartburn in the evening before sleeping though because I simply don't eat foods that cause me severe heartburn for dinner. I usually veggies with cheese or grilled fish fillet. Or sometimes I go for Amaranth/Chickpeas, nuts and chia seeds. Either way I just avoid foods that cause heartburn so that my sleep won't be bothered.