Just keep knitting. Having a stitch fall off the tip of the needle isn't so horrible. You can pick it up again. Just put the tip of the needle into it. Confidence comes with putting stitches back on the needle and learning to make corrections. The free videos here (button at the top of the page) show how to fix things. You might find the demo of a small project video helpful. The main thing is, just keep at it and before long you'll wonder what you were so worried about. At least that's how it was for me.
I should never overestimate my basic arithmetic skills.