It sounds like your defeating yourself before you even get into queue, give yourself some credit and go in with an open mind. If you explain at the start of a duty that you are still getting the grasp of your job then most ppl will offer advice and be understanding. Try going with a cpl tanks from your fc that also heal or dps so they can see what you are doing and offer advice. You can look me up as well and i can run a cpl things with you when i'm on.