I get it. You're nervous. Nothing's for certain. It could all go wrong, Etc, etc, etc.
On one level of course you're perfectly right. Taking back the House and other Democratic gains aren't for certain. It could indeed go wrong. But.....the stubborn fact remains that the situation continues to look good and there's no obvious reason to be pessimistic at this point. Read this excellent Josh Marshall piece to help you calm down.
And then read the long Jonathan Martin/Alexander Burns piece in the Times about the ever-expanding House playing field and how stretched the GOP is trying to defend more and more seats.
Nothing's for certain but some outcomes are far more likely than others.