Scaling up position size after a good run — how do you manage the psychological aspect?

I've been trading a small account for a while now, mostly paper trading initially and then with very small positions on some ETFs and $MSFT. I've had a decent win rate recently, nothing to write home about, but consistent enough that I'm starting to feel more confident in my analysis. The logical next step, according to all the books, is to slowly increase my position size. However, the thought of putting more capital on the line, even with the same risk parameters (e.g., still risking 1% per trade, just 1% of a larger 'notional' value), is suddenly bringing back some of the early hesitancy and fear of loss that I thought I'd moved past. It's almost like the numbers on the screen are more real now. For those who've gone through this, how did you mentally bridge that gap from small stakes to genuinely meaningful position sizes without letting fear or overconfidence derail your process?