Fyi you're charging a lot less than I used to when doing contract work that predominantly involved wordpress template brochure websites.
The biggest mistake you can make as a contractor is underpricing yourself. Not only does it hurt the market but you can find yourself in situations where you can't work enough hours to cover taxes, downtime, benefits like health insurance, much less a vacation. Then you start making mistakes like overbooking yourself to make up the difference and do a crappy job with all of your projects.