How to continue losing weight?

Hi, there! I need some advice! Almost 2 years ago, I was about 235 lbs and made the decision to change my life and begin a health and fitness journey. I started out with absolutely 0 knowledge on health and fitness and this was probably the billionth time swearing to myself that I was for real this time about losing weight. I was 22, pre-diabetic, and had been overweight since about the age of 8. I come from a long line of obeseity on both sides of my family. For some reason, this time it just stuck. I lost around 10 lbs the first month completely on my own, and that was the deal my doctor and I made in order for her to prescribe me a magic weight loss pill to help me lose (Adipex). Adipex is a drug designed for weight loss in obese adults that can be perscribed for 3 months. Most adults lose around 15 lbs during the 3 months without changing their diet and activity level however, I lost about 30 lbs while on it because I was determined and with the help of MFP and my new found love for fitness, I had quite the success. Even after getting off that pill, I still continued to lose and make progress, which was a huge relief. I lost about 60-65 lbs my first 6 months and then hit the dreaded plateau. I didn't continue to lose again until around another 6 months later and ever since losing an additional 15 pounds very slowly the past year, my weight loss is just extremely slow, to where it's like I'm losing a pound every 2 months, if that... When I first started losing, the weight was melting off because I was going from a high calorie, high fat, high carb, disgusting diet and 0 activity to the complete opposite. I'm going on 2 years of an overall healthy lifestyle and I'm the queen at maintaining my weight, even if I have high calorie days weekly, but I cannot seem to lose. I'm so frustrated! I've learned a heck of a lot about health and fitness and weight loss in general so I know that I'm just taking in more calories than I'm putting out but my motivation to go back to logging every single meal and really stick to counting calories again is almost non-existent. Idk what's wrong with me. I do really well throughout the week but then the weekend's come and it's like I lose all self control then when I weigh-in during the week, I'm happy to see I haven't gained, but angry that I haven't lost. I'm currently about 155 lbs and I won't be happy until I'm 125 lbs. I want that 110 lb weight loss total. I won't be happy until I hit that. I work so hard in the gym and I've changed the way I eat completely and I know my problem is simple. Just eat 1400-1500 calories per day and no more, because when I stick to that throughout the week, I start losing, but Friday night hits and I'm making excuses and letting myself go until Monday again. I'm so irritated with myself because when I was way heavier and way more addicted to bad foods in the very beginning, my discipline was perfect and no matter how hard I craved, I could tell myself no and move on. What's wrong with me now? If anything, I feel it should be easier for me now to get back on track and easily lose the rest of this weight. I'm just so tired of being stuck. Any advice would be greatly appreciated! Thank you!!!