Horrible Yeast infection. Anyone had the same? Worried???

I started seeing this guy and I knew I was clean before you know getting DTB and he told me he was clean too.

Anyways.... we had sex without protection - I know silly me- at the same time I took a pill for a sore throat and it was a medicine I had never taken.

And so I have a pretty nasty Yeast infection (I’ve had them before but ir had been almost a year since I got one) and I am treating with OTM.

Its just the timing of it all its so weird and idk if I should be alarmed. From when I had sex to getting the infection it only passed like 2-3 days so it would be waaay to soon to show symptoms for an STI right?