yeah like i get everything you are saying about the FDA and all that, and how doctors tend not to know about 'minor' or 'alternate' substances. i am listening. honestly it's probably a good job I found you on here you do know a lot and have experience with ADs, which sound hit or miss like you said but more on the side of 'miss'.
like 5htp before would usually be alright to use every other week or so, safe like that, for a measured serotonin boost in the absence of taking anything else that could boost serotonin.
It's really hard to say what it could be. How long did you have sex? Was it rough? Could you just be experiencing some tenderness from that?
It could be all a rebound effect from what you took - and why are you taking those? Do you have ED? If you don't, you don't need those, and in most places, they aren't regulated.
I'd give it 24-48 hours before really worrying, and if it's not better, see your doctor. If you notice anything like a rapid heart rate, shortness of breath, etc., see your doctor.