Hi
Have a look at our “Know your chances” web page, it provides information on your chances of getting or passing an STI depending on how you are having sex.
http://smartsexresource.com/about-stis/know-your-chances-0
I have never heard of a sex worker using a used condom with a client in Canada. Most condoms that are used come with lubricant already in them. I wonder if that is what you saw in the condom.
It may also be helpful to go and visit a clinic and talk to a health professional about your situation. Have a look at our clinic finder for a clinic in your area.
http://smartsexresource.com/get-tested/clinic-finder
Please leave a comment to let us know if this answers your question or if you need more information.
Health Nurse
For other readers, please feel free to leave a comment, or let us know if this was helpful.