Ok, first, Scott gave you some really good advice in his last post, I'd suggest following it.
Second, many people find food logs helpful in that they tell you exactly how much you ate on a daily/weekly/monthly basis. Your seeming inability to know exactly how much you're eating is a good indication that you might want to start keeping one again.
Or, alternatively you could do as I do. I figured out how much protein I need to be consuming to promote muscle gain and to prevent muscle loss, and how many calories I need to take in. I then figured out how much of each type of food that I would need to eat to reach those levels. Every morning I weigh out the amount of each type of food that I will need to consume (if you don't own a food scale, they're a good investment) and take that food with me to eat throughout the day.
I eat every 2-3 hours (sometimes more frequently depending on time constraints) and just make sure that I finish all of my food for the day. Sure, it's not exact as I don't actually carry my food scale around with me, but it really doesn't matter all that much either. If I finish my food I get enough calories. If I eat every 2-3 hours I know I'm always providing my body with fuel and it never has to break down my body for energy.
As far as a training log, this is absolutely positively crucial if you want to continue building. As Stronghold alluded to, you aren't going to get bigger if you aren't providing your body with overload. If your numbers have been the same for longer than 2 consecutive workouts, then it's time to change exercises and work on getting as strong as possible on the new ones.
You need to either lift more weight on the bar, or the same weight for more repetitions each and every workout. You need to force your body to adapt. Without a good reason to do so (progressive overload) your body has no reason to build more muscle.
If you find that you can't improve from workout to workout, then either:
1) you're not getting enough nutrition to allow for repair and growth
2) you're not giving your body enough time between sessions to improve
3) you're not getting enough sleep
4) a combination of several of the above
You're also going to need to take rest/back-off weeks every now and then as the body can't handle going balls to the wall week in and week out indefinitely. So, when you start to feel chronically fatigued, or irritable, or you lose your drive to train, take a back-off week or two (10-14 days works well for a lot of people). Then hit it hard again. Rinse and repeat.