Yep, we're in the same boat.

Mine is due to medication I'm on, which not only gives me no appetite, but improves my concentration so much that I get wrapped up in what I'm doing and actually forget it's time to eat.

I was at 120 pounds a year ago, and I did not notice the first 10 pounds I lost. But the next 10, yeah--I knew something didn't feel right. I slept 14 hours a day, I wasn't hungry, etc. You just know when something doesn't feel right. It turns out it IS my medicine causing this, but right now I don't have any backup options where I can just stop taking it.

They're right--you do just have to eat more, and more often, when you can manage it. So do I. It's still you in there, just a more careful you. In general though, as a rule of thumb, trust what your body is saying. You know when it's a problem and when you need to change course. Hang in there!