Not likely that you contracted an STD from receiving fellatio, but your still at risk, get checked, ease your mind. NGU is short for Non-gonococcal Urethritis, which is basically saying that you have inflammation of the urethra without the presence of Gonorrhea.
-Good Luck
Your doctor can do an urine test to look for ngu. If you were tested for stds and were negative but still have symptoms, return for follow up.
grace
Also- I forgot to mention that my exposure was revieving fellatio only. I am not sure if this matters for NGU or not. Thanks.