I can appreciate your anxiety, since I took an unplanned week off after totally burning out on my program from overtraining/undereating, and developing some subtle joint issues. It was just one week, but going back in, I felt nervous and tentative about performing lifts I was confident on only a week or so earlier. I was afraid my barely-healed joints would end up worse, and I'd be laid off for a lot longer. Fortunately, after my first workout I felt better, my joints felt stronger. That was a month ago and my workouts, joints and recovery have been steadily improving.
There may be some supplements that will help you, but primarily, I'd say your struggle is mental. Just start back, and go slow. Drop your expectations. Forgive yourself for not being where you were, and want to be. Accept that, and do what feels good for your body. This is not a time to push too hard, physically, it's a time to test the waters. The grit will be a mental grit, as well as a commitment to yourself to listen to your body and respect and heed what it tells you.
You'll start getting stronger soon, and then your confidence will return and you'll start looking forward to workouts with eager anticipation again.
Taking gear just to feel mentally prepared, well that's just a terrible reason, in my opinion. Be brave and embrace the mental challenge. If you feel you need to take something, start with something that will actually help your injury heal and help your body recover from the workouts. Consider this a test of your 'real' strength; your mental strength. Bodybuilding is as much about mental strength and attitude as it is about physical strength.
Good luck, you can do it!