No! please don't think that way! For some reason, parents always do that and treat situations like that as though it was a joke. I hate that. Anyways, I really admire your art and I'm pretty sure that there are tons of people who care for you probably more than I do. So please, just try to think a little more positive. I apologize if I sound ignorant but I don't really know much about having depression.
*also, I reeeaaally love your artstyle ^v^

Adults have a tendency to think that kids/young adults don't have "real problems", when mental illness can affect literally anyone.

Anyways, that doesn't mean your problems aren't important or should be dismissed. If you're having problems, you've gotta keep pushing for help. Don't give up on yourself, either!!

i agree with venoshade, many parents just think its a cry for attention. Have you tried a hotline? I heard those can help very well. I know it would be difficult with anxiety, but it doesn't hurt to try.

To add to what's already been said:
Your parents probably think it's nothing serious because 1) it's the first time you've mentioned it--thus (to them) it's something new, right now it's just a 'phase' and 2) you're their baby and they won't /want/ to think anything's wrong with you--which is how they could miss clues in your actions that point to the truth of your words. They /want/ it to be a phase, they /want/ it to just be that you're shy/don't get out of the house often enough/whatever. The only way to convince them that it's /not/ a phase is to show them that it's persistent, that it's not going away. Keep bringing it up, keep showing them it's still there, but don't--I repeat /don't/--keep quiet about it. Doing that will only further convince them that it's a phase, a passing problem, and nothing to worry about. But if you keep talking about it, they'll /have/ to take you seriously at some point or another. You have to take it upon yourself to show them that it's serious.

cont.
If you drop it, if you don't outwardly treat it as something serious, they won't either. They're your parents, and that means two things: 1) it will take some effort to convince them because they want to believe everything about their child is always perfect and 2) once they are convinced, they will have your back to the end and be your strongest support.
Suffering in silence will not solve anything--in fact, it generally makes things worse. The only way to get help is to ask for it, to convince people that it's needed.
Best of luck; my prayers go with you.
-Akira