Perhaps what you're eating doesn't contain what your body is lacking in terms of proteins/vitamins/nutrients.

The feeling of hunger is due to the body letting you know that it's running out of something. It may just be after any old food that can be converted into energy to help fuel your body, but it can also be like a lack of iron, fatty acids, etc.

When it's a lack like that, eating what you normally eat (or eating more of what you've already eaten) won't resolve the issue because it won't have given the body what it's trying to tell you it needs. That's actually why a lot of people struggle with putting on unwanted weight. What they're eating isn't what the body wants so it causes them to overeat to try to feel full, but because the body doesn't like to waste it stores all that extra away for the future.

If the meatballs don't work try some fruits & veggies or nuts. The other night I was in a similar situation, unable to fill up. I'd eaten my dinner but felt like I hadn't eaten anything at all, despite my stomach feeling full. I hadn't had an orange for a while so I tried that, and by halfway through I felt full.