The problem is that there was a huge dot-com surge at the end of the millenium, and everyone and their brother became a web designer... did well too, mostly. But when that caved in, unemployed webbies were a dime a dozen. Still are.
Make sure you have *other* skills as well... page layout, illustration... hell, even powerpoint... so that you can be more marketable. And you don't need fancy certificates in them, just some solid experience. You should do okay if you can do that.