Lecomtes,
Don't short change yourself. Your 20 pound weight loss in January wasn't due to luck. Sure, part of it may have been water weight. But you put a lot of hard work and effort into that loss. Give yourself some credit girl!
There is nothing wrong with setting your goals high. Having said that, cut yourself some slack too and don't place too lofty expectations upon yourself. A goal of 25 pounds in 5 weeks would anticipate the same or greater rate of loss as you experienced in the first month. People generally do not have that rate of weight loss continue past the first month. It is normally for the rate to slow down going forward. It fluctuates from person to person depending on a variety of factors. The danger of setting an unrealistic goal is the disappointment you might experience if you don't meet it. If it won't get you down, go for it! But if it will totally depress you to the point of giving up if you don't meet your goal, then I would shoot for something a little lower. I think a more realistic goal would be 2-3 pounds per week. (But don't be disappointed if you lose 1 pound or remain the same weight one week. It happens. And then some weeks you may lose 4). Plateaus or slow downs in weight loss happen to everyone. If you let a slow down or stall in your weight loss bring you down, you run the danger of falling off your plan. As one wise person on this board says, weight loss is not linear. Just because you follow the same plan from week to week does not mean you are automatically going to get the same results. Unfortunately it doesn't work that way.
I know you want to take the weight off as quickly as possible. We all do. It is a huge rush to see the numbers on the scale go down. In fact, I think I am addicted to that. Its a big part of my incentive to stay on my plan. But think about it. Even if you lose 2 pounds per week, that's 100 pounds in a year. We didn't gain all our weight all at once. So, we shouldn't get frustrated if it takes a year or so to come off.
One thing I learned from this experience is that I had to find what worked for me. What works for others may not be best for you. If you have the patience to write down your food intake, count calories, etc. - that is a great idea. Personally I don't have the patience to count points or calories. So a low carb paleo / primal like diet works for me. I don't plan on being that restrictive forever. I will add certain foods back into my diet when I reach my goal. But for now that is helping me lose at a fast pace. For other people, other methods such as calorie counting or weight watchers works. You just have to find out what works for you. In the past I lost weight, but then reverted to my old bad habits and diet. What I have finally realized from years of losing and regaining is that I had to make a change in my eating lifestyle which will last me my whole life. You have to find a way of eating that you can live with long term. But first you have to find a plan that will help you reach your goals. It sounds like you found it since what you've been doing is working. I have tinkered and modified my plan as I have gone along, adding foods, then subtracting some, until I found out what works and what doesn't. I also had to eliminate some bad habits that I developed, like late night snacking. That killed my weight loss.
Anyway, best of luck on your weight loss!