Doesn’t sound to me like there’s anything to worry about. Unless you are really trying to push the envelope in terms of weight gain or weight loss, then eating when you’re hungry (as you’ve been doing) is about the most natural thing in the world.
Were you really trying to get bigger, then you’d have to eat more than your body is asking for, and were you trying to lose weight then obviously your body wants more food than you’ve giving it.
But as for the burning muscle thing - if you were eating so little that this could be a problem, you would be hungry. And I don’t mean a little hungry, I mean really fucking hungry, in which case I think you would probably eat something, no?
You would have to have some very weird health and metabolic problems for your body’s hunger levels to naturally only want to eat fewer calories than is required to actually maintain it, so I think you’re probably good.
A lot of things can affect appetite and, for whatever reason, yeah you might have to force down a little more than you want to, but it’s no big deal. Like mentioned earlier - obviously you’ll need to eat a little more food than you’re comfortable with but it doesn’t have to become an endurance exercise; simply eat until you’re full and then a little more if you can manage it.
I’m assuming that you just want to be a healthy weight, rather than bodybuilder sized, so there’s no need to really force it.
This line of thinking is not productive. Your situation isn’t bad or even really unusual so make sure you’re not dramatising it in your mind.