Anytime I'm nervous or unsure about doing something "hard" (like getting my Master's), I remind myself of all the dumb people I know who have already done it. If they could do it, so can you, I tell myself.
Generally, this pep talk works and whatever I was anxious about doesn't turn out to be as hard as I'd thought. This is NOT the case with student teaching. I'm struggling hard and all the reminders aren't making me feel any better.. in fact, they're beginning to make me wonder if those dummies (and all those awful teachers) were secretly smarter than I am.