This does not sound like an STD. This is morw like. Physical trauma rather than std.
How long has it been since you could get it up? I personally never heard of any STD causing ED, especially complete ED within 24 hours. Any physical injury? Stress? And I’ve had sex before and not been able to get back up for a bit and I’ve had sex where after completion, I still have a decent erection. Your body is never consistent, like how your lifts can be good one day and poor the next. If it hasn’t been long, and there’s no reason to assume the worst, then don’t worry yourself with something like a STD that kills dicks