Be positive

This is something I find hard at times.
Today is a good example. I got to work and starting feeling a bit off. I left midway through the day and spent the rest of the afternoon worried about all manner of things to do with my health.
I thought I was past that. I have a particular issue at the moment that is more annoying than anything else which is being treated and it hasn't healed up just yet.
So today I got all wound up about these things. I did take some action with relaxation and some anti-anxiety methods but I seem to end up having to resort to this.
Being positive doesn't come easy to me, unfortunately.