Well, this starts with the idiocy of self-diagnosis and taking an antibiotic without proof of an infection. That is exactly how real infections get out of control. Antibiotics do a lot of damage to your body and taking them unsupervised, for the wrong number of days, switching varieties, using someone else's, taking the wrong dosage, and taking them when you don't have an actual infection is going to HARM you.
There are no less than four things that come to mind with burning urination. You have already thought of a sexually transmitted disease (which is why you probably mistakenly self-prescribed an antibiotic). There is a urinary tract infection, which men only get for one of three reasons, all highly unlikely reasons. There is the small tear in the urethra, which is a likely cause, and about which almost nothing can be done except have patience for it to heal. There are parasites you can get from seafood, unaffected by antibiotics of course, because they're not bacteria. And there's also allergies, a change in laundry detergent, food, fabric, or many other things. It could also be early formation of kidney stones, at the stage when crystals are smaller than sand and may not be visible to the naked eye.
Drinking alcohol can change the sensations during urination for several reasons.
The ER made a mistake treating you for an STD without first confirming with a test for bacteria. That test would likely have come up negative anyway because you'd been taking antibiotics already. And as you can see, it was a mistake because it made no difference. Going to the ER for this kind of condition is also a mistake because it's not an emergency.
I understand the desire to take care of yourself quickly, but you are not a doctor and shouldn't act like one. So many things wrong with this approach...but rather than berate you further, how about some useful instructions?
Promptly make an appointment with a UROLOGIST. A general practitioner is not going to know enough about genitalia to be useful. It's going to cost a lot less in time and money, and you'll actually get results and an accurate diagnosis. That way you can do something about the situation that gets you feeling normal again.
In the meantime, make sure with your actual doctor's advice, you can stop the antibiotics you mistakenly have been taking. Then go buy some probiotics to take for a month, to fix the damage to your immune system you didn't intend.