Worried From a Combination of Symptoms

Dear folks,

Since the last two years, i have been extremely stressed and worried. I've had the following exposures. Although i feel them to be low risk, but the symptoms i'm experiencing are making crazy and unable to explain. Please read my situations below and kindly advice.

Oct 2005:- Exposure with a female partner of unknown status. For some reason, even before I touched her, I observed a lot of precum and she was scared. I just wiped it off, and then engaged in getting a HJ with a lot of fluid (lotion and probably other secretions), but was careful to avoid touching the tip of my penis with any fluids.

Nov 2005:- 49 days test was neg for all STD's.
Also, I was told i had extreme vitamin B12 deficiency. Been taking 2 b12 tablets daily.

April 2006:- Sudden onset of bad sore throat. Doc thought its tonsils, was put on a 10 day Bactrum dosage to cure the bacteria.

July 2006:- One low risk exposure with a partner of unknown status. Sucked her nipples for a few minutes and was given a HJ without a condom.

December 2006:- One low risk exposure with a partner of unknown status, who had a 2 year baby. Not sure if she was still breastfeeding her kid.
I sucked her nipples for about 5 mins or so, did not feel any liquid going into my mouth.
Was also given a Handjob with condom on.

December 2006 thru now: Recurring sore throats (atleast thrice in three months), a lot of visible veins suddenly on arms and chest, sudden fluctuations in weight and a lot of heartburn.

April 2007:- Caught a cold, and a little sore throat. Doc thought it was viral, but also prescribed me a ten day dosage (3 per day – 500 mg each) of Amoxycillin antibiotics and asked me to take them only if I develop a lot of phlegm only. However, with the first onset of a little dry cough, I panicked and started taking the entire dosage of antibiotics. I was fine for a few days.

May 2007:- Started feeling a bitter taste in my mouth and saw my tongue was white. Ignored it for a few days, but it got worse. Went to doctor, but did not tell about my sexual exposures. However, I mentioned about the antibiotics.
He prescribed anti fungal lozenges (5 per day) for about 10 days which I did. Two weeks later, the white tongue still remains (on and off) along with the bitter taste. Early in the morning, I can see small deposits on the tongue, which I scrape them off and keep chewing gum or some spicy items to wither off the taste. Each time after scraping off, I am fine for a few hours, and then it comes back. Its been almost a month now with the tongue symptoms. thats the scary part.

Please advice for what risks i was at and is any testing warranted for any STDs?
Does extreme stress put me at risk for any of the symptoms OR make it worse?
I have read so so many articles on all this, and i am just living day and night with only these thoughts. Sorry for any trouble.

I appreciate all your responses.

Thanks for your time.

Regards
Roger