Garbeth

You typically get designers, Front end Devs and back-end devs. I'd go with what you enjoy to be honest, you might just be more comfortable with front end right now as you have a little more experience with it.
 
Here are some essential things you'll need to know for a front end dev:
HTML CSS + Responsive implementation JavaScript + jQuery framework And here are some less important but could be considered essential skills if you wanna become a more senior front end developer
CSS preprocessors such as SASS and LESS Front end framework i.e. (Bootstrap) Version control (Git) Automated task running (Grunt being the best I've come across) Experience in command line for using GIT and SSH. FTP will rarely be used by a professional web developer, it's slow! Emmet - formerly zen coding, allows you to write html much faster. Basic Photoshop (or graphic editor) skills to create image sprites and so on. Good knowledge of performance - what affects page load time. JS MV*C frameworks, Backbone, Angular I've almost certainly missed some out there, but it gives you an idea of the fairly vast array of things you can learn to advance your front end skillset, The first list being a minimum to get you a junior role. Any acronyms there you don't understand or have never heard of Google will give you a great insight into them

You want to (fairly quickly) decide which path you wish to take - front end developer or back end developer. If you wanna be a front end developer then you will be wasting your time learning PHP and MySQL. You'll need to know JavaScript for both (ajax, json is often dealt with by back end devs, JavaScript frameworks such as Node.js are increasingly used server-side too).
If you wanna be a back end developer then you don't need to be super great with CSS and HTML, but a basic understanding is always good.
 
If you wanna be a front end dev learning the core fundamentals of CSS is far more important the CSS3 trickery like transitions etc, without knowledge of the box model, positioning, floats, clearfixes, box-sizing and so on work you won't get very far at all.
 
Don't try to be a jack of all trades, Web development covers a very wide spectrum, one that's so wide it's virtually impossible to master everything, find what you like and are good at and specialize at that. For example JavaScript alone takes thousands of hours to master. and then there's all the frameworks on top of that.

thanks a lot for your advice.