If I had unprotected sex and contracted an STI is it possible to pass that on within 48 hours?

pretty much as per the title. Unprotected sex with concern of contracting an sti. Sex 48 hours later and concern I've caught and passed something on. Being tested next week. Help please?

You dont say why you think you have an STI Stuart. Do you have any symptoms?

Some STI's like HIV take a long time to incubate but it rather depends which one

I would say it is likely. Altho symptoms don’t show for most things until a few weeks later.  But it probably depends on the STI you’re worried about.