There's no way to know what you are eating if you don't weigh and measure. You might not have to do it forever, but if you are this stuck, I would absolutely do it.
Yes, I have lost (and regained) 100+ pounds twice, I'm on my third go (totally normal for anyone significantly overweight... 99% of us relapse). First time I was 17 so I just quit eating and started running. Second time was about four years ago and I used the ww'er system to track my food and exercise (using a heart rate monitor during exercise). Presently I use straight up calorie counting and a BodyBugg / BodyMedia continual metabolic meter and am down 30 pounds.
Congrats on your weight loss! That's really impressive and inspiring.
About calorie counting? How do you get the required protein and maintain low calories? I'm trying to build muscles :-)
Well first of all if you are really 40 lbs overweight you might not be able to see the changes. And regardless you probably won't see too much change in only 2 months. Keep it up though. After 6 months, if you are on a linear progression, the weights will be heavy, your body will be changing and you'll be hungry for sure.
This is why I'm sure other people with other areas of experience and knowledge will chime in. When you are very overweight you don't really have to worry about that- you flush out enough protein with the fat loss that the body recycles. In the last couple of years I did triathlons and half-marathons, so I don't think I was having any trouble getting the fitness I needed and I just wasn't worried about protein levels. Right now I'm running at about 50% fat, 15% carbs and 35% protein and 1000 cal/day shortages... but I'm just in a totally different boat.
You are in a different situation where tiny changes matter more and like SBhikes pointed out, progress runs on a bit longer timeline.
I thought I was 60 lbs over weight when i started strength training, but realized recently that I was skinny fat. My mom always commenting on my size, an hers. "Anything above a 0 is fat". So I'm thinking 40 lbs and a bunch of muscles