If you get paid for what you do you may consider yourself a professional but you'd be wrong. Getting paid for what you do here and there or 'sometimes' doesn't make you Pro. When a neighbor asks your son to help her with her garbage by dragging it out to the curb and she gives him a couple of dollars for doing it, it doesn’t make him a professional garbage hauler. So getting paid to do a singular task isn’t the standard.
Professionalism falls into two distinct categories, which can and often do overlap: When what you get paid to do covers your living expenses (i.e., you're actually doing it to make a living or it covers a significant part of your living expenses) you're a paid professional. If you have a regular job that pays your living expenses and you do a particular thing on the side, which you get paid for, and those employing you are paying you for your expertise in that field you could be considered a professional hobbyist. In that case you're being paid for your acquired skill set and that sets the standard for your being a professional.
The other side of professionalism is a bit more esoteric. If you're obsessed with having the work you do be the very best it can be and you don't sleep on any aspect of it, you can also consider yourself a professional. The distinction here comes in understanding what 'not sleeping' on any aspect of the work is. An example of this would be: in comics if you write well, draw and color well but your lettering sucks and you don't hire a letterer to have that component work well too, you're not yet a true professional even if someone is willing to pay for your work.
Creators able to see the flaws in the work they do and make the adjustments will always be far more professional than those that just 'get it out.' This speaks to the professional attitude a creator cultivates which usually overlaps and is the basis for getting paid or for getting paid better for the work you do create.