Will I ever test negative for syphilis

[Sadgirl0411]

I'm a 25 year old hetro sexual female. January 25th I was diagnosed and treated for syphilis. I was under the impression that I was allergic to penicillin so I was treated with doxycycline for 28 because of my high titer 1:256 During that time I drank atleast 3 times a week because of depressed I was with this. I also threw up a few times. April 6th I went to my gyn told them my situation and was retested. Of course it came back positive my dr gave me more doxycycline for 2 weeks. Not letting me know that I will test positive for some time. I couldn't deal with the doxycycline anymore so I returned to the health department where I was first tested and asked for the penicillin shot because at this point I didn't care about a slight reaction(my gyn and primary provider refused). The health department got a hold of my new results and was pleased with the numbers 1:16 which happend over 70 days. I still have about a weeks worth of doxycycline which I am going to finish even though it makes me very sick. I was just wondering if there anyone who tested positive for syphilis and if you ever tested negative again if so how long did it take?  Also at what titer are you no longer contagious? Just thought I would ask people who've been through this.