A little bit late after your crash, but there's no reason to crash from a speed wobble. They are entirely manageable. As mentioned above, clamping your knee to the top tube will kill the vibration.

Also, most anything you do to change the frequency can stop it, i.e. shift weight back, loosen elbows.

The worst thing you can do it tighten up, which you likely did.

You can also stop speed wobbles by changing your speed. You can actually pedal through them and they'll stop as you reach a higher speed, of course you can also gently slow to stop them

Key is to know that they are controllable and will not crash the bike.

The rider however can crash the bike by tightening up and overreacting.

I've ha speed wobbles above 50 mph and lived to tell the tale.