A 29 y.o. male should not have difficulty getting an erection. You said you saw a urologist who gave you the meds and he didn’t think anything was wrong. Did he perform any testing on you or do any blood work? He referred you to a therapist because he feels since your plumbing is fine it must be in your head (the one on your shoulders).
Have you masturbated lately? Do you still get turned on by the sight of a naked woman or man? Try the postage stamp test to check your erection. Get a small roll of postage stamps and wrap once around your dick flaccid and seal the ends. If you get a nocturnal erection the stamps will come apart. If it turns out you have ED you need to see a cardiologist ASAP. If some of the smallest vessels in your body are clogged than other more important small vessels are clogged or on that path. Reality sucks!