Get lots of P/T in. Try a 1 hour run first thing in the morning, and again at least 2 hours before retiring to sleep. Remember if you are training in the evening, you need a couple of hours to wind down if you are to get good sleep.
Not only will this help you relax
, it will give you time to reflect on things which are going wrong, what you are doing right, shift a sense of perspective back into your training. I mean having a think about things during the exercise.
Also you might like to use the time training to envisage likely situations with flying, and mentally go through the procedures involved. If you target this at a heart rate of around 140 bpm you can be better assured of your performance under test conditions.
Best of luck. I had a similar problem with my performance in a different field some years ago (competition music) and the above worked very well within around one month.
Hope this helps,
LF