Question about doxycycline

I had unprotected sex about 5 weeks ago and a couple of days later it burned while I urinated.  I am a male.  I took an std test for chlamydia and gonnorea and they both came back negative but the doctor gave diflucan thinking it might be a yeast infection.  It worked for about a week and then the burning came back.  The doctor then gave me doxycycline( 10 days 2 pills easch day) and said that this should work.  It works a little but he said it might take a week and its been six days.  I have a couple of questions.

1. I've been doing alot of heavy drinking the past couple of days, would that affect the effects of doxycycline?

2. Would it make my penis kinda sore too?  The diflucan did and then the burning went away.

3. The doctor said that the diflucan I originally took could of changed my ph level in my pee so that it wouldnt burn for a week.  Is there any truth in that?

4. The diflucan worked, if the doxycycline doesnt should I just try to get a stronger medicine that can take care of a yeast infection.

[Emma_08]

1.  I don't think your alcohol consumption should have an affect on the effectiveness of the doxy.  There are sometimes interactions between alcohol and antibiotics, but it should not stop it from working.
2.  I don't think so.
3.  I have never heard of this, but I don't know.
4.  If you had a yeast infection, the Diflucan should have taken care of it.  If your symptoms are not completely relieved, you need to go back to the doctor for further evaluation.  Also, yeast infections in men are not very common, so it is possible something else is causing your symptoms.
Good luck,
Em