Different bodies need different amounts of energy from food to function. It is true that some people have very small appetites compared to others, and those people seem to eat very little BUT, even the person with the smallest appetite should still maintain a regular eating pattern. They will eat smaller amounts at meal times, but not skip meals. The fact that you are doing this, suggests to me that there may be something else going on. Could it be that you are not eating precisely because you are feeling pressure to do so? Then psychological reasons may be playing a prominent role in determining your intake, and that is never a good place to be in because our emotions don’t know what is good for our bodies!
I’d suggest talking to a nutrition therapist that can look at your diet objectively and make some suggestions for changes.
 A healthy appetite and good food are a great daily pleasure to be enjoyed - don’t let anything get in the way of that!