How to stay motivated with weight loss

I really just want to lose 15-20 pounds but if i don’t see a difference within a week I just give up again and go back to eating like shit. How do I stay motivated and consistent and not give up and start seeing actual results? I’m not going to the gym just going on walks it’s really my diet that needs to change, I eat normally during the day then overeat in the middle of the night. Any advice is appreciated

Edit @Casey ma’am I don’t expect a miracle. It’s just my mindset, I used to have an eating disorder and I was very good at losing weight and just not eating in general. Now it’s a lot harder for me because I actually eat now and I get discouraged. That doesn’t mean I expect to lose weight in a week. I just needed advice on how to keep myself motivated, not how to lose 20 lbs in a week. Your condescending “advice” does not help anyone.. at all.