I am currently "between" drivers myself as a habitual buyer/seller of clubs to find the perfect blend. Have I missed it? no.
My SIM2 3 wood @15 degrees is my new driver! Averaging 250 yds from the tee with it and finding so many more fairways leading to more GIR. A much simpler game of golf from the fairway and the confidence has spread to other aspects of my game. Find a club to tee off that you are confident with and you will swing smoother and with freedom-this will lead to more FIR and lower scores. It can be a 3 wood, 5 wood even a hybrid, I for one am content sacrificing a few yards for less sideways recovery shots from rough and trees!
Welcome to the real world OP, no matter how hard we try range play and practice rounds are a million miles away from scorecard in hand stroke-play. The ultimate test for all us golfers!
I used to fear Medal (stroke play) competitions after having similar "out of the blue" blow ups. Over time I have learnt to embrace the challenge and temper my strategy accordingly.
Try to find some stableford events to ease yourself into competitive golf-much more forgiving as a blow up hole and loss of stableford points can be recovered more easily than an 8 marked down during stroke-play.
As has been said, from a gameplan for each hole, relax and try your best to execute it. When trouble pops up extract yourself minimising scorecard damage and move on!