First of all, your original plan is to buy this big house and enjoy it for a long time, right? If so, start enjoy it, will you?
Since you can afford the payment, why not stop worrying about losing equity now? If you look at it long term, by the time you retire (say in 15 years), the market will be well recovered and you can sell and retire comfortably.
Why people love to buy high & sell low?????
You should buy low & sell high!!! If you don’t see the opportunity present itself and you have the money power to stay the course, STAY THE COURSE.
Face the reality, you miss the peak and now it’s too late to make the most out of your house, so forget and forgive yourself. Live your life and try to enjoy every minute of it.