I won't tell you that you are an idiot. You may be ****ed lucky though. I'm presuming the engine still turns over, no squeaks or nothing indicating that it's tight, right?. If you are running JASO MA spec oil and not cheap Quaker State, Full synthetic has a lot of lubricity even without oil pressure, oil pressure you don't have anymore. Probably though, the only thing that would suffer almost immediately would be the camshaft blocks as the cams both run in the aluminum cast head with no bearings whatsoever and the head isn't rebuildable. It's replaceable only.
You need to pull the front of the engine. The radiator needs to come off and the complete clutch cover need to be removed to access the pump, sprocket and drive chain. I'd suggest in the very least a Triumph Shop Manual. It's all described on pages 9.12 and 9.13. The pressure pump is accessible and removable without splitting the cases. The scavenge pump isn't. You may be very lucky.
I've heard of no one snapping the pump shaft or loosing that chain. Maybe the divot in the cover accelerated the problem. Sounds like a likely cause to me.
Put the friggin front fender back on. You ain't no teeney bopper.