How to overcome healer anxiety

Sprout here, have been playing sporadically for little over half a year now. Been mainly DPS and due RL commitments amount of playtime has been lowish, MSQ progress is at post-Stormblood now.

However, playing as a summoner is slowly beginning to feel that it isn't really my cup of tea. Got some gear for scholar and tried few runs with FC mates and for my great surprise playing as a healer felt rather fun. And here comes the "but", our FC is formed with couple RL friends and when we are all online there is just enough people for one dungeon party. And it is not that many days in week we are all online same time.

I understand that the anxiety would ease after some experience but the main problem is that there is a very, very uncomfortable feel playing with strangers especially at some critical role. Heck, even with friends there is constant feeling "what if I f*** up".

I'm pretty sure I'm not alone with this feeling and many of you have found out ways to overcome that feeling. I'm writing this in hopes that you share your stories and perhaps there would be some help for anxiety.