This is what you'd call a Mary Sue or self-inset character. I feel like it's unavoidable for all creators to a certain extent. Consciously or not, we write based on things we know/understand. Same goes for drawing, we are most familiar with how our own selves look, so that might end up rubbing off onto our characters.
On the other hand, since I'm aware of these things, I try to give my comic characters traits that I do not have. For example, sarcastic, secretly tough, fatherly, accent, etc. Also, I try to make them look physically different. For example, different height, hair, clothes, etc.
Here's a self portrait of me vs. my main cast: