Firstly forming new habits can really help. I am a bit the same, suffer from anxiety that stems from nothing other than me looking at the glass half empty for much of the time. I recently started a blog where I give thanks, for anything and everything. I have found that pure and simple gratitude has changed my life and the way I look at it. I was initially blogging each day and it eased up a little now, but if I find myself going back to thinking negatively I go back and start being thankful. You could try something similar, keeping a journal or something and you will find it won't take long before your whole outlook changes from making a conscious decision about it.

There are lots of articles out there about gratitude, there is a page on FB called 365 Grateful the Documentary - worth having a look, and what triggered my shift was a book called One Thousand Gifts. Good luck - as Sopdet said sounds like you have taken the first step oxoxox