It's very hard to do new things. The fear of the unknown is something a lot of people deal with. As for the stress and anxiety, sometimes the fear of having stress and anxiety can make the anxiety MUCH worse... so sometimes it is ok just to accept that the anxiety is going to happen instead of trying to prevent it.

When you feel the anxiety coming on just focus on your breathing and try to remember that whatever you are doing, there is a good reason and it is a step in the right direction.