Have you done the postage stamp test for a few nights (to see if it's waking up overnight when you're likely less anxious and far more relaxed)? If it fails that then I urge you to see a doctor to try to dig into the possible cause(s).
In what way is this affecting you? Is it when you are with someone and are about to have intercourse or is it when alone pleasuring yourself? Just give me a few more details please.