I was diagnosed later, at 25, so I had developed a lot of anxiety over things. This is because I couldn’t get stuff done and it stressed me out.
Once I started the meds, a lot of that anxiety went away because I could finally get a handle on my life. However, old habits die hard and I found myself still dealing with some horrible avoidance issues, so I also spent some time with a therapist doing cognitive behavioral therapy (and just some talk therapy, too). I highly recommend The Feeling Good Handbook by David Burns – this is self-directed CBT exercises that can help you get a handle on depressive/anxious thought patterns. I used this in between therapy sessions to help me identify and tackle anxious thoughts.
PS: Anyone telling you that you’re “too nervous” to be good at work is a jerk.