How did you get past "FAT BRAIN"?
Think of your new stomach as a new born baby. It only needs a small amount to be full. That baby will rapidly become an adult. In six months you will be able to eat a lot more. At thirteen years out, I could eat as much as I did before surgery.
One of these days, you will look back longingly on this period when a teaspoon of food is so filling. This is called the honeymoon period. Take advantage of it to lose as much weight as possible and to gain good eating habits.
When you eat less food than you burn, your body will burn its stored fat to make up for what is not coming in. That is why the surgery makes you lose weight.
Real life begins where your comfort zone ends
I still measure and weigh some things even at five years out (I don't worry about things like vegetables since they don't have that many calories, but I still weigh things like meat and cheese). I also started counting calories when I was several months out (maybe a year out?). Once I hit maintenance, I experimented with different calorie levels to see how many I needed to maintain my weight. I discovered that I can maintain my weight if I consistently eat between 1500-1700 calories a day (and that range is going to vary for everyone - some can eat more, some less). It's not that I never go over 1700 calories - I occasionally do. But when I do, I cut back on other days or really beef up my exercise that week.
if I want to lose weight, I consistently eat at the low end of my range, or under it. If I start consistently eating over my range, my weight will start to head up.
so yes - it's a daily thing, and I'll have to do this for the rest of my life. But that's OK. I'll do whatever it takes to avoid weighing over 300 lbs again!